diff --git a/core/assocs/assocs-docs.factor b/core/assocs/assocs-docs.factor
index e85789a4f2..687e60621e 100755
--- a/core/assocs/assocs-docs.factor
+++ b/core/assocs/assocs-docs.factor
@@ -69,10 +69,10 @@ ARTICLE: "assocs-lookup" "Lookup and querying of assocs"
 ARTICLE: "assocs-sets" "Set-theoretic operations on assocs"
 "It is often useful to use the keys of an associative mapping as a set, exploiting the constant or logarithmic lookup time of most implementations (" { $link "alists" } " being a notable exception)."
 { $subsection subassoc? }
-{ $subsection intersect }
+{ $subsection assoc-intersect }
 { $subsection update }
-{ $subsection union }
-{ $subsection diff }
+{ $subsection assoc-union }
+{ $subsection assoc-diff }
 { $subsection remove-all }
 { $subsection substitute }
 { $subsection substitute-here }
@@ -260,7 +260,7 @@ HELP: values
 
 { keys values } related-words
 
-HELP: intersect
+HELP: assoc-intersect
 { $values { "assoc1" assoc } { "assoc2" assoc } { "intersection" "a new assoc" } }
 { $description "Outputs an assoc consisting of all entries from " { $snippet "assoc2" } " such that the key is also present in " { $snippet "assoc1" } "." }
 { $notes "The values of the keys in " { $snippet "assoc1" } " are disregarded, so this word is usually used for set-theoretic calculations where the assoc in question either has dummy sentinels as values, or the values equal the keys." } ;
@@ -270,11 +270,11 @@ HELP: update
 { $description "Adds all entries from " { $snippet "assoc2" } " to " { $snippet "assoc1" } "." }
 { $side-effects "assoc1" } ;
 
-HELP: union
+HELP: assoc-union
 { $values { "assoc1" assoc } { "assoc2" assoc } { "union" "a new assoc" } }
 { $description "Outputs a assoc consisting of all entries from " { $snippet "assoc1" } " and " { $snippet "assoc2" } ", with entries from " { $snippet "assoc2" } " taking precedence in case the corresponding values are not equal." } ;
 
-HELP: diff
+HELP: assoc-diff
 { $values { "assoc1" assoc } { "assoc2" assoc } { "diff" "a new assoc" } }
 { $description "Outputs an assoc consisting of all entries from " { $snippet "assoc2" } " whose key is not contained in " { $snippet "assoc1" } "." } 
 ;
diff --git a/core/assocs/assocs-tests.factor b/core/assocs/assocs-tests.factor
index c4db604784..76f484006d 100755
--- a/core/assocs/assocs-tests.factor
+++ b/core/assocs/assocs-tests.factor
@@ -58,24 +58,24 @@ H{ } clone "cache-test" set
 ] [
     H{ { "factor" "rocks" } { "dup" "sq" } { 3 4 } }
     H{ { "factor" "rocks" } { 1 2 } { 2 3 } { 3 4 } }
-    intersect
+    assoc-intersect
 ] unit-test
 
 [
     H{ { 1 2 } { 2 3 } { 6 5 } }
 ] [
     H{ { 2 4 } { 6 5 } } H{ { 1 2 } { 2 3 } }
-    union
+    assoc-union
 ] unit-test
 
 [ H{ { 1 2 } { 2 3 } } t ] [
-    f H{ { 1 2 } { 2 3 } } [ union ] 2keep swap union dupd =
+    f H{ { 1 2 } { 2 3 } } [ assoc-union ] 2keep swap assoc-union dupd =
 ] unit-test
 
 [
     H{ { 1 f } }
 ] [
-    H{ { 1 f } } H{ { 1 f } } intersect
+    H{ { 1 f } } H{ { 1 f } } assoc-intersect
 ] unit-test
 
 [ { 1 3 } ] [ H{ { 2 2 } } { 1 2 3 } remove-all ] unit-test
diff --git a/core/assocs/assocs.factor b/core/assocs/assocs.factor
index adb69d317c..4a6ecae4fe 100755
--- a/core/assocs/assocs.factor
+++ b/core/assocs/assocs.factor
@@ -109,17 +109,17 @@ M: assoc assoc-clone-like ( assoc exemplar -- newassoc )
         >r over r> hashcode* 2/ >r dupd hashcode* r> bitxor
     ] { } assoc>map hashcode* ;
 
-: intersect ( assoc1 assoc2 -- intersection )
+: assoc-intersect ( assoc1 assoc2 -- intersection )
     swap [ nip key? ] curry assoc-subset ;
 
 : update ( assoc1 assoc2 -- )
     swap [ swapd set-at ] curry assoc-each ;
 
-: union ( assoc1 assoc2 -- union )
+: assoc-union ( assoc1 assoc2 -- union )
     2dup [ assoc-size ] bi@ + pick new-assoc
     [ rot update ] keep [ swap update ] keep ;
 
-: diff ( assoc1 assoc2 -- diff )
+: assoc-diff ( assoc1 assoc2 -- diff )
     swap [ nip key? not ] curry assoc-subset ;
 
 : remove-all ( assoc seq -- subseq )
diff --git a/core/bootstrap/layouts/layouts.factor b/core/bootstrap/layouts/layouts.factor
index ceb011d52b..e839576bc9 100755
--- a/core/bootstrap/layouts/layouts.factor
+++ b/core/bootstrap/layouts/layouts.factor
@@ -36,4 +36,4 @@ tag-numbers get H{
     { word 17 }
     { byte-array 18 }
     { tuple-layout 19 }
-} union type-numbers set
+} assoc-union type-numbers set
diff --git a/core/classes/classes.factor b/core/classes/classes.factor
index b22e21eb92..4f43b86f64 100755
--- a/core/classes/classes.factor
+++ b/core/classes/classes.factor
@@ -89,7 +89,7 @@ M: word reset-class drop ;
     dup reset-class
     dup deferred? [ dup define-symbol ] when
     dup word-props
-    r> union over set-word-props
+    r> assoc-union over set-word-props
     dup predicate-word
     [ 1quotation "predicate" set-word-prop ]
     [ swap "predicating" set-word-prop ]
diff --git a/core/generator/generator.factor b/core/generator/generator.factor
index 7858205384..919e89d3c8 100755
--- a/core/generator/generator.factor
+++ b/core/generator/generator.factor
@@ -202,7 +202,7 @@ M: #dispatch generate-node
 : define-if>boolean-intrinsics ( word intrinsics -- )
     [
         >r [ if>boolean-intrinsic ] curry r>
-        { { f "if-scratch" } } +scratch+ associate union
+        { { f "if-scratch" } } +scratch+ associate assoc-union
     ] assoc-map "intrinsics" set-word-prop ;
 
 : define-if-intrinsics ( word intrinsics -- )
diff --git a/core/io/streams/nested/nested.factor b/core/io/streams/nested/nested.factor
index 6b8953f86e..fd67910b6f 100755
--- a/core/io/streams/nested/nested.factor
+++ b/core/io/streams/nested/nested.factor
@@ -45,7 +45,7 @@ C: <ignore-close-stream> ignore-close-stream
 TUPLE: style-stream < filter-writer style ;
 
 : do-nested-style ( style style-stream -- style stream )
-    [ style>> swap union ] [ stream>> ] bi ; inline
+    [ style>> swap assoc-union ] [ stream>> ] bi ; inline
 
 C: <style-stream> style-stream
 
diff --git a/core/optimizer/backend/backend.factor b/core/optimizer/backend/backend.factor
index e6b7533756..3237f095bf 100755
--- a/core/optimizer/backend/backend.factor
+++ b/core/optimizer/backend/backend.factor
@@ -17,7 +17,7 @@ SYMBOL: optimizer-changed
 GENERIC: optimize-node* ( node -- node/t changed? )
 
 : ?union ( assoc/f assoc -- hash )
-    over [ union ] [ nip ] if ;
+    over [ assoc-union ] [ nip ] if ;
 
 : add-node-literals ( assoc node -- )
     over assoc-empty? [
@@ -82,7 +82,7 @@ M: node optimize-node* drop t f ;
     2dup at* [ swap follow nip ] [ 2drop ] if ;
 
 : union* ( assoc1 assoc2 -- assoc )
-    union [ keys ] keep
+    assoc-union [ keys ] keep
     [ dupd follow ] curry
     H{ } map>assoc ;
 
diff --git a/core/parser/parser.factor b/core/parser/parser.factor
index 4b4fae7a0c..65abd6c83c 100755
--- a/core/parser/parser.factor
+++ b/core/parser/parser.factor
@@ -501,14 +501,14 @@ SYMBOL: interactive-vocabs
     ] if ;
 
 : filter-moved ( assoc1 assoc2 -- seq )
-    diff [
+    assoc-diff [
         drop where dup [ first ] when
         file get source-file-path =
     ] assoc-subset keys ;
 
 : removed-definitions ( -- assoc1 assoc2 )
     new-definitions old-definitions
-    [ get first2 union ] bi@ ;
+    [ get first2 assoc-union ] bi@ ;
 
 : removed-classes ( -- assoc1 assoc2 )
     new-definitions old-definitions
diff --git a/core/sbufs/sbufs-tests.factor b/core/sbufs/sbufs-tests.factor
index b30812b06f..ac3f565e56 100644
--- a/core/sbufs/sbufs-tests.factor
+++ b/core/sbufs/sbufs-tests.factor
@@ -19,6 +19,6 @@ IN: sbufs.tests
 
 [ SBUF" x" ] [ 1 <sbuf> CHAR: x >bignum over push ] unit-test
 
-[ fixnum ] [ 1 >bignum SBUF" " new length class ] unit-test
+[ fixnum ] [ 1 >bignum SBUF" " new-sequence length class ] unit-test
 
 [ fixnum ] [ 1 >bignum [ ] SBUF" " map-as length class ] unit-test
diff --git a/core/sequences/sequences-tests.factor b/core/sequences/sequences-tests.factor
index 281b27d540..8d0a91e384 100755
--- a/core/sequences/sequences-tests.factor
+++ b/core/sequences/sequences-tests.factor
@@ -240,7 +240,7 @@ unit-test
 
 [ ?{ f t } ] [ 0 2 ?{ f t f } subseq ] unit-test
 
-[ V{ f f f } ] [ 3 V{ } new ] unit-test
+[ V{ f f f } ] [ 3 V{ } new-sequence ] unit-test
 [ SBUF" \0\0\0" ] [ 3 SBUF" " new ] unit-test
 
 [ 0 ] [ f length ] unit-test
diff --git a/core/source-files/source-files.factor b/core/source-files/source-files.factor
index b385fbf369..5703b631f4 100755
--- a/core/source-files/source-files.factor
+++ b/core/source-files/source-files.factor
@@ -69,7 +69,7 @@ M: pathname forget*
     pathname-string forget-source ;
 
 : rollback-source-file ( file -- )
-    dup source-file-definitions new-definitions get [ union ] 2map
+    dup source-file-definitions new-definitions get [ assoc-union ] 2map
     swap set-source-file-definitions ;
 
 SYMBOL: file
diff --git a/core/vectors/vectors-tests.factor b/core/vectors/vectors-tests.factor
index 18aa0f3fa7..8f64265771 100755
--- a/core/vectors/vectors-tests.factor
+++ b/core/vectors/vectors-tests.factor
@@ -94,6 +94,6 @@ IN: vectors.tests
     100 >array dup >vector <reversed> >array >r reverse r> =
 ] unit-test
 
-[ fixnum ] [ 1 >bignum V{ } new length class ] unit-test
+[ fixnum ] [ 1 >bignum V{ } new-sequence length class ] unit-test
 
 [ fixnum ] [ 1 >bignum [ ] V{ } map-as length class ] unit-test
diff --git a/extra/cocoa/messages/messages.factor b/extra/cocoa/messages/messages.factor
index 5ae02ec66a..ca9509c3ec 100755
--- a/extra/cocoa/messages/messages.factor
+++ b/extra/cocoa/messages/messages.factor
@@ -139,7 +139,7 @@ H{
     { "NSRect" "{_NSRect=ffff}" }
     { "NSSize" "{_NSSize=ff}" }
     { "NSRange" "{_NSRange=II}" }
-} union alien>objc-types set-global
+} assoc-union alien>objc-types set-global
 
 : objc-struct-type ( i string -- ctype )
     2dup CHAR: = -rot index* swap subseq
diff --git a/extra/delegate/protocols/protocols.factor b/extra/delegate/protocols/protocols.factor
index 736645890e..f1ad068fe2 100755
--- a/extra/delegate/protocols/protocols.factor
+++ b/extra/delegate/protocols/protocols.factor
@@ -5,7 +5,7 @@ io definitions kernel continuations ;
 IN: delegate.protocols
 
 PROTOCOL: sequence-protocol
-    clone clone-like like new new-resizable nth nth-unsafe
+    clone clone-like like new-sequence new-resizable nth nth-unsafe
     set-nth set-nth-unsafe length set-length lengthen ;
 
 PROTOCOL: assoc-protocol
diff --git a/extra/help/markup/markup.factor b/extra/help/markup/markup.factor
index b963a19f29..2e2b34ebfd 100755
--- a/extra/help/markup/markup.factor
+++ b/extra/help/markup/markup.factor
@@ -79,7 +79,7 @@ M: f print-element drop ;
     [ strong-style get print-element* ] ($heading) ;
 
 : ($code-style) ( presentation -- hash )
-    presented associate code-style get union ;
+    presented associate code-style get assoc-union ;
 
 : ($code) ( presentation quot -- )
     [
diff --git a/extra/http/server/actions/actions.factor b/extra/http/server/actions/actions.factor
index fabddcdeb1..2b2aaea6a8 100755
--- a/extra/http/server/actions/actions.factor
+++ b/extra/http/server/actions/actions.factor
@@ -40,7 +40,7 @@ TUPLE: action init display submit get-params post-params ;
 M: action call-responder ( path action -- response )
     '[
         , ,
-        [ +append-path associate request-params union params set ]
+        [ +append-path associate request-params assoc-union params set ]
         [ action set ] bi*
         request get method>> {
             { "GET" [ handle-get ] }
diff --git a/extra/http/server/sessions/sessions.factor b/extra/http/server/sessions/sessions.factor
index 1288b4f7a4..d41b54e156 100755
--- a/extra/http/server/sessions/sessions.factor
+++ b/extra/http/server/sessions/sessions.factor
@@ -84,7 +84,7 @@ TUPLE: url-sessions ;
     [ drop ] [ get-session ] 2bi ;
 
 : add-session-id ( query -- query' )
-    session-id get [ session-id-key associate union ] when* ;
+    session-id get [ session-id-key associate assoc-union ] when* ;
 
 : session-form-field ( -- )
     <input
diff --git a/extra/io/launcher/launcher.factor b/extra/io/launcher/launcher.factor
index c5cd7b24eb..9b480d0cc2 100755
--- a/extra/io/launcher/launcher.factor
+++ b/extra/io/launcher/launcher.factor
@@ -85,8 +85,8 @@ M: process hashcode* process-handle hashcode* ;
 : get-environment ( process -- env )
     dup environment>>
     swap environment-mode>> {
-        { +prepend-environment+ [ os-envs union ] }
-        { +append-environment+ [ os-envs swap union ] }
+        { +prepend-environment+ [ os-envs assoc-union ] }
+        { +append-environment+ [ os-envs swap assoc-union ] }
         { +replace-environment+ [ ] }
     } case ;
 
diff --git a/extra/tools/deploy/config/config.factor b/extra/tools/deploy/config/config.factor
index 7ebedf7ca1..589d6c613b 100755
--- a/extra/tools/deploy/config/config.factor
+++ b/extra/tools/deploy/config/config.factor
@@ -65,7 +65,7 @@ SYMBOL: deploy-image
         { deploy-c-types?           f }
         ! default value for deploy.macosx
         { "stop-after-last-window?" t }
-    } union ;
+    } assoc-union ;
 
 : deploy-config-path ( vocab -- string )
     vocab-dir "deploy.factor" append-path ;
@@ -73,7 +73,7 @@ SYMBOL: deploy-image
 : deploy-config ( vocab -- assoc )
     dup default-config swap
     dup deploy-config-path vocab-file-contents
-    parse-fresh dup empty? [ drop ] [ first union ] if ;
+    parse-fresh dup empty? [ drop ] [ first assoc-union ] if ;
 
 : set-deploy-config ( assoc vocab -- )
     >r unparse-use string-lines r>
diff --git a/extra/tools/deploy/shaker/strip-cocoa.factor b/extra/tools/deploy/shaker/strip-cocoa.factor
index de8f8740f0..038bfde70d 100755
--- a/extra/tools/deploy/shaker/strip-cocoa.factor
+++ b/extra/tools/deploy/shaker/strip-cocoa.factor
@@ -9,14 +9,14 @@ global [
     [ "MiniFactor.nib" load-nib ] cocoa-init-hook set-global
 
     ! Only keeps those methods that we actually call
-    sent-messages get super-sent-messages get union
-    objc-methods [ intersect ] change
+    sent-messages get super-sent-messages get assoc-union
+    objc-methods [ assoc-intersect ] change
 
     sent-messages get
     super-sent-messages get
     [ keys [ objc-methods get at dup ] H{ } map>assoc ] bi@
-    super-message-senders [ intersect ] change
-    message-senders [ intersect ] change
+    super-message-senders [ assoc-intersect ] change
+    message-senders [ assoc-intersect ] change
 
     sent-messages off
     super-sent-messages off
diff --git a/extra/tuple-arrays/tuple-arrays.factor b/extra/tuple-arrays/tuple-arrays.factor
index b9593af239..454a1c0b58 100644
--- a/extra/tuple-arrays/tuple-arrays.factor
+++ b/extra/tuple-arrays/tuple-arrays.factor
@@ -11,7 +11,7 @@ TUPLE: tuple-array example ;
     swap tuple>array length over length - ;
 
 : <tuple-array> ( length example -- tuple-array )
-    prepare-example [ rot * { } new ] keep
+    prepare-example [ rot * { } new-sequence ] keep
     <sliced-groups> tuple-array construct-delegate
     [ set-tuple-array-example ] keep ;
 
diff --git a/extra/ui/commands/commands.factor b/extra/ui/commands/commands.factor
index f73276bbe6..90eb6254cd 100755
--- a/extra/ui/commands/commands.factor
+++ b/extra/ui/commands/commands.factor
@@ -66,7 +66,7 @@ M: word command-description ( word -- str )
     H{ { +nullary+ f } { +listener+ f } { +description+ f } } ;
 
 : define-command ( word hash -- )
-    default-flags swap union >r word-props r> update ;
+    default-flags swap assoc-union >r word-props r> update ;
 
 : command-quot ( target command -- quot )
     dup 1quotation swap +nullary+ word-prop
diff --git a/extra/ui/operations/operations.factor b/extra/ui/operations/operations.factor
index a9009e386e..26200ea96f 100755
--- a/extra/ui/operations/operations.factor
+++ b/extra/ui/operations/operations.factor
@@ -54,7 +54,7 @@ SYMBOL: operations
     H{ { +keyboard+ f } { +primary+ f } { +secondary+ f } } ;
 
 : define-operation ( pred command flags -- )
-    default-flags swap union
+    default-flags swap assoc-union
     dupd define-command <operation>
     operations get push ;
 
diff --git a/extra/unicode/data/data.factor b/extra/unicode/data/data.factor
index b6449f6a0f..58d836464c 100755
--- a/extra/unicode/data/data.factor
+++ b/extra/unicode/data/data.factor
@@ -135,7 +135,7 @@ load-data
 dup process-names \ name-map set-value
 13 over process-data \ simple-lower set-value
 12 over process-data tuck \ simple-upper set-value
-14 over process-data swapd union \ simple-title set-value
+14 over process-data swapd assoc-union \ simple-title set-value
 dup process-combining \ class-map set-value
 dup process-canonical \ canonical-map set-value
     \ combine-map set-value
diff --git a/extra/xml/data/data.factor b/extra/xml/data/data.factor
index a7c8bf7b73..da2e4ccb32 100755
--- a/extra/xml/data/data.factor
+++ b/extra/xml/data/data.factor
@@ -62,7 +62,7 @@ M: attrs set-at
     ] if* ;
 
 M: attrs assoc-size attrs-alist length ;
-M: attrs new-assoc drop V{ } new <attrs> ;
+M: attrs new-assoc drop V{ } new-sequence <attrs> ;
 M: attrs >alist attrs-alist ;
 
 : >attrs ( assoc -- attrs )