diff --git a/README.md b/README.md
index fd8da9e..7c8b4e0 100644
--- a/README.md
+++ b/README.md
@@ -87,17 +87,17 @@ type Options struct {
 	// e.g., You can use embed.FS to copy files from embedded filesystem.
 	FS fs.FS
 
-	// NumberOfWorkers represents the number of workers used for
+	// NumOfWorkers represents the number of workers used for
 	// concurrent copying contents of directories.
 	// If 0 or 1, it does not use goroutine for copying directories.
 	// Please refer to https://pkg.go.dev/golang.org/x/sync/semaphore for more details.
-	NumberOfWorkers int64
+	NumOfWorkers int64
 
 	// PreferConcurrent is a function to determine whether or not
 	// to use goroutine for copying contents of directories.
 	// If PreferConcurrent is nil, which is default, it does concurrent
 	// copying for all directories.
-	// If NumberOfWorkers is 0 or 1, this function will be ignored.
+	// If NumOfWorkers is 0 or 1, this function will be ignored.
 	PreferConcurrent func(srcdir, destdir string) (bool, error)
 }
 ```
diff --git a/all_test.go b/all_test.go
index 6256b0b..13bae07 100644
--- a/all_test.go
+++ b/all_test.go
@@ -476,14 +476,14 @@ func (r *SleepyReader) Read(p []byte) (int, error) {
 	return n, e
 }
 
-func TestOptions_NumberOfWorkers(t *testing.T) {
-	opt := Options{NumberOfWorkers: 3}
+func TestOptions_NumOfWorkers(t *testing.T) {
+	opt := Options{NumOfWorkers: 3}
 	err := Copy("test/data/case19", "test/data.copy/case19", opt)
 	Expect(t, err).ToBe(nil)
 }
 
 func TestOptions_PreferConcurrent(t *testing.T) {
-	opt := Options{NumberOfWorkers: 4, PreferConcurrent: func(sd, dd string) (bool, error) {
+	opt := Options{NumOfWorkers: 4, PreferConcurrent: func(sd, dd string) (bool, error) {
 		return strings.HasSuffix(sd, "concurrent"), nil
 	}}
 	err := Copy("test/data/case19", "test/data.copy/case19_preferconcurrent", opt)
diff --git a/benchmark_test.go b/benchmark_test.go
index 0817440..3a3e153 100644
--- a/benchmark_test.go
+++ b/benchmark_test.go
@@ -5,33 +5,33 @@ import (
 	"testing"
 )
 
-func BenchmarkOptions_NumberOfWorkers_0(b *testing.B) {
+func BenchmarkOptions_NumOfWorkers_0(b *testing.B) {
 	var num int64 = 0 // 0 or 1 = single-threaded
-	opt := Options{NumberOfWorkers: num}
+	opt := Options{NumOfWorkers: num}
 	for i := 0; i < b.N; i++ {
 		Copy("test/data/case19", fmt.Sprintf("test/data.copy/case19-%d-%d", num, i), opt)
 	}
 }
 
-func BenchmarkOptions_NumberOfWorkers_2(b *testing.B) {
+func BenchmarkOptions_NumOfWorkers_2(b *testing.B) {
 	var num int64 = 2
-	opt := Options{NumberOfWorkers: num}
+	opt := Options{NumOfWorkers: num}
 	for i := 0; i < b.N; i++ {
 		Copy("test/data/case19", fmt.Sprintf("test/data.copy/case19-%d-%d", num, i), opt)
 	}
 }
 
-func BenchmarkOptions_NumberOfWorkers_4(b *testing.B) {
+func BenchmarkOptions_NumOfWorkers_4(b *testing.B) {
 	var num int64 = 4
-	opt := Options{NumberOfWorkers: num}
+	opt := Options{NumOfWorkers: num}
 	for i := 0; i < b.N; i++ {
 		Copy("test/data/case19", fmt.Sprintf("test/data.copy/case19-%d-%d", num, i), opt)
 	}
 }
 
-func BenchmarkOptions_NumberOfWorkers_8(b *testing.B) {
+func BenchmarkOptions_NumOfWorkers_8(b *testing.B) {
 	var num int64 = 8
-	opt := Options{NumberOfWorkers: num}
+	opt := Options{NumOfWorkers: num}
 	for i := 0; i < b.N; i++ {
 		Copy("test/data/case19", fmt.Sprintf("test/data.copy/case19-%d-%d", num, i), opt)
 	}
diff --git a/copy.go b/copy.go
index 6662f84..2979af9 100644
--- a/copy.go
+++ b/copy.go
@@ -22,8 +22,8 @@ type timespec struct {
 // Copy copies src to dest, doesn't matter if src is a directory or a file.
 func Copy(src, dest string, opts ...Options) error {
 	opt := assureOptions(src, dest, opts...)
-	if opt.NumberOfWorkers > 1 {
-		opt.intent.sem = semaphore.NewWeighted(opt.NumberOfWorkers)
+	if opt.NumOfWorkers > 1 {
+		opt.intent.sem = semaphore.NewWeighted(opt.NumOfWorkers)
 		opt.intent.ctx = context.Background()
 	}
 	if opt.FS != nil {
diff --git a/options.go b/options.go
index 978484a..1fbfcb1 100644
--- a/options.go
+++ b/options.go
@@ -68,17 +68,17 @@ type Options struct {
 	// e.g., You can use embed.FS to copy files from embedded filesystem.
 	FS fs.FS
 
-	// NumberOfWorkers represents the number of workers used for
+	// NumOfWorkers represents the number of workers used for
 	// concurrent copying contents of directories.
 	// If 0 or 1, it does not use goroutine for copying directories.
 	// Please refer to https://pkg.go.dev/golang.org/x/sync/semaphore for more details.
-	NumberOfWorkers int64
+	NumOfWorkers int64
 
 	// PreferConcurrent is a function to determine whether or not
 	// to use goroutine for copying contents of directories.
 	// If PreferConcurrent is nil, which is default, it does concurrent
 	// copying for all directories.
-	// If NumberOfWorkers is 0 or 1, this function will be ignored.
+	// If NumOfWorkers is 0 or 1, this function will be ignored.
 	PreferConcurrent func(srcdir, destdir string) (bool, error)
 
 	// Internal use only
@@ -161,7 +161,7 @@ func assureOptions(src, dest string, opts ...Options) Options {
 }
 
 func shouldCopyDirectoryConcurrent(opt Options, srcdir, destdir string) (bool, error) {
-	if opt.NumberOfWorkers <= 1 {
+	if opt.NumOfWorkers <= 1 {
 		return false, nil
 	}
 	if opt.PreferConcurrent == nil {