diff --git a/data.go b/data.go
index ce69695..cf5448d 100644
--- a/data.go
+++ b/data.go
@@ -28,10 +28,10 @@ func (s dataSource) name(p string) string {
 }
 
 // loadData loads every source into one namespace tree and returns its root
-// children. A directory becomes a group; each *.json file in it compiles to a node
+// children. A directory becomes a folder; each *.json file in it compiles to a node
 // keyed by its base name (address.json -> "address"); each subdirectory becomes a
-// nested group, so folders turn into dot-path segments. Sources merge left to right:
-// matching groups merge by their children, and any other clash is won by the last
+// nested folder, so folders turn into dot-path segments. Sources merge left to right:
+// matching folders merge by their children, and any other clash is won by the last
 // source loaded. Once merged, linkRefs binds every reference against the
 // final tree.
 func loadData(sources []dataSource) (map[string]node, error) {
@@ -74,15 +74,15 @@ func loadData(sources []dataSource) (map[string]node, error) {
 	return root, nil
 }
 
-// loadDir compiles one directory into a group. fs.ReadDir yields entries sorted
+// loadDir compiles one directory into a folder. fs.ReadDir yields entries sorted
 // by name, so the tree is built deterministically. Empty subdirectories (no JSON
 // anywhere under them) are skipped rather than added as empty namespaces.
-func loadDir(src dataSource, dir string) (*group, error) {
+func loadDir(src dataSource, dir string) (*folder, error) {
 	entries, err := fs.ReadDir(src.fsys, dir)
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", src.name(dir), err)
 	}
-	g := &group{children: map[string]node{}}
+	g := &folder{children: map[string]node{}}
 	for _, e := range entries {
 		if strings.HasPrefix(e.Name(), ".") { // hidden: a checkout or an editor's file, never data
 			continue
@@ -99,8 +99,8 @@ func loadDir(src dataSource, dir string) (*group, error) {
 	return g, nil
 }
 
-// loadFolder adds a subdirectory as a nested group, unless nothing under it is data.
-func loadFolder(src dataSource, g *group, full, name string) error {
+// loadFolder adds a subdirectory as a nested folder, unless nothing under it is data.
+func loadFolder(src dataSource, g *folder, full, name string) error {
 	child, err := loadDir(src, full)
 	if err != nil {
 		return err
@@ -117,7 +117,7 @@ func loadFolder(src dataSource, g *group, full, name string) error {
 
 // loadFile compiles a *.json file into a category named after it; any other file
 // is skipped.
-func loadFile(src dataSource, g *group, full, file string) error {
+func loadFile(src dataSource, g *folder, full, file string) error {
 	if !strings.HasSuffix(file, ".json") {
 		return nil
 	}
@@ -141,13 +141,13 @@ func loadFile(src dataSource, g *group, full, file string) error {
 	return nil
 }
 
-// mergeChildren overlays src onto dst. Two groups under the same key merge
+// mergeChildren overlays src onto dst. Two folders under the same key merge
 // recursively (so locales/categories from several paths combine); every other
 // key is replaced, making the last-loaded directory win on a conflict.
 func mergeChildren(dst, src map[string]node) {
 	for k, v := range src {
-		if dg, ok := dst[k].(*group); ok {
-			if sg, ok := v.(*group); ok {
+		if dg, ok := dst[k].(*folder); ok {
+			if sg, ok := v.(*folder); ok {
 				mergeChildren(dg.children, sg.children)
 				continue
 			}
diff --git a/fejkdata.go b/fejkdata.go
index 24bcf7e..b19e785 100644
--- a/fejkdata.go
+++ b/fejkdata.go
@@ -142,10 +142,10 @@ func (f *Generator) List() []string {
 }
 
 // paths lists the dot paths addressable from n, relative to it, where "" is n
-// itself. A group has no value of its own, so it contributes only its children's.
+// itself. A folder has no value of its own, so it contributes only its children's.
 func paths(n node) []string {
 	switch n := n.(type) {
-	case *group:
+	case *folder:
 		var out []string
 		for _, name := range sortedNames(n.children) {
 			for _, p := range paths(n.children[name]) {
diff --git a/graph.go b/graph.go
index 5e6acc0..06d525f 100644
--- a/graph.go
+++ b/graph.go
@@ -51,7 +51,7 @@ type namedNode struct {
 
 func contained(n node) []namedNode {
 	switch n := n.(type) {
-	case *group:
+	case *folder:
 		return named(n.children)
 	case *choice:
 		out := make([]namedNode, len(n.items))
@@ -69,7 +69,7 @@ func contained(n node) []namedNode {
 // named skips a bound {/path} key: it is a render edge, not containment, so using
 // it as a path segment would report a node under a path that does not reach it. Only
 // a template's fields hold bindings — loadDir skips a dot-prefixed entry, so a
-// group's children never carry the prefix — so this one skip serves both.
+// folder's children never carry the prefix — so this one skip serves both.
 func named(m map[string]node) []namedNode {
 	out := make([]namedNode, 0, len(m))
 	for _, name := range sortedNames(m) {
@@ -111,7 +111,7 @@ func (e renderEdge) reached() string {
 
 // renderEdges lists the children rendering n recurses into, mirroring expand: a
 // choice's items, and a template's field/reference tokens plus its operands. A
-// group renders nothing, so it has no edges.
+// folder renders nothing, so it has no edges.
 func renderEdges(n node) []renderEdge {
 	switch n := n.(type) {
 	case *choice:
diff --git a/node.go b/node.go
index e1dc797..5374aa2 100644
--- a/node.go
+++ b/node.go
@@ -13,12 +13,12 @@ import (
 // re-sums weights.
 type node interface{ isNode() }
 
-// group is a namespace of named children, built from a directory of JSON files
+// folder is a namespace of named children, built from a directory of JSON files
 // and subdirectories. It has no value of its own: descend into a named child by
 // dot path; rendering one is an error (see Fake).
-type group struct{ children map[string]node }
+type folder struct{ children map[string]node }
 
-func (*group) isNode() {}
+func (*folder) isNode() {}
 
 // choice picks one of its items. cum holds cumulative weights for a weighted
 // pick; when nil the choice is uniform and selection is O(1). shared is the set of
diff --git a/path.go b/path.go
index ea4fbe1..f997eed 100644
--- a/path.go
+++ b/path.go
@@ -16,7 +16,7 @@ type pathWalk struct {
 	leaf   func(n node) error
 }
 
-// walkPath descends tail from n: a group or template by its next segment, a
+// walkPath descends tail from n: a folder or template by its next segment, a
 // choice by w.choice, which consumes no segment. A missing segment is an error,
 // so no walk reaches past what the data holds. A table-shaped dispatch, one case
 // per node kind, kept whole on purpose.
@@ -28,7 +28,7 @@ func walkPath(n node, tail []string, w pathWalk) error {
 		return nil
 	}
 	switch n := n.(type) {
-	case *group:
+	case *folder:
 		child, ok := n.children[tail[0]]
 		if !ok {
 			return fmt.Errorf("no entry %q", tail[0])
diff --git a/reference.go b/reference.go
index 08f209e..46f8751 100644
--- a/reference.go
+++ b/reference.go
@@ -162,17 +162,17 @@ func eachTemplate(root map[string]node, fn func(folder []string, path string, t
 		}
 		return nil
 	}
-	var inFolder func(folder []string, children map[string]node) error
-	inFolder = func(folder []string, children map[string]node) error {
+	var inFolder func(dir []string, children map[string]node) error
+	inFolder = func(dir []string, children map[string]node) error {
 		for _, name := range sortedNames(children) {
-			path := join(strings.Join(folder, "."), name)
-			if g, ok := children[name].(*group); ok {
-				if err := inFolder(append(folder[:len(folder):len(folder)], name), g.children); err != nil {
+			path := join(strings.Join(dir, "."), name)
+			if g, ok := children[name].(*folder); ok {
+				if err := inFolder(append(dir[:len(dir):len(dir)], name), g.children); err != nil {
 					return err
 				}
 				continue
 			}
-			if err := inCategory(folder, path, children[name]); err != nil {
+			if err := inCategory(dir, path, children[name]); err != nil {
 				return err
 			}
 		}
@@ -183,13 +183,13 @@ func eachTemplate(root map[string]node, fn func(folder []string, path string, t
 
 // resolveCategory walks a dotted path through the folders to the category it
 // names, returning that head, the node, and the tail left to read into it. A
-// descent of its own rather than a walkPath: it walks groups only and returns
+// descent of its own rather than a walkPath: it walks folders only and returns
 // where they end, not a leaf.
 func resolveCategory(root map[string]node, segments []string) (head []string, target node, tail []string, err error) {
-	var n node = &group{children: root}
+	var n node = &folder{children: root}
 	i := 0
 	for ; i < len(segments); i++ {
-		g, ok := n.(*group)
+		g, ok := n.(*folder)
 		if !ok {
 			break
 		}
@@ -199,7 +199,7 @@ func resolveCategory(root map[string]node, segments []string) (head []string, ta
 		}
 		n = child
 	}
-	if _, ok := n.(*group); ok {
+	if _, ok := n.(*folder); ok {
 		return nil, nil, nil, fmt.Errorf("names a folder, not a value")
 	}
 	return segments[:i], n, segments[i:], nil
diff --git a/render.go b/render.go
index 71a5902..90a74fb 100644
--- a/render.go
+++ b/render.go
@@ -20,11 +20,11 @@ type rng interface {
 func (f *Generator) Fake(path string) (string, error) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
-	n, err := descend(f.rand, &group{children: f.categories}, strings.Split(path, "."))
+	n, err := descend(f.rand, &folder{children: f.categories}, strings.Split(path, "."))
 	if err != nil {
 		return "", fmt.Errorf("fejkdata: %s: %w", path, err)
 	}
-	if _, ok := n.(*group); ok {
+	if _, ok := n.(*folder); ok {
 		return "", fmt.Errorf("fejkdata: %s names a folder, not a value", path)
 	}
 	return renderOnce(f.rand, n), nil