diff --git a/promql/functions.go b/promql/functions.go
index 98bc3ad54..d5a4e4899 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -892,8 +892,8 @@ func funcDayOfWeek(ev *evaluator, args Expressions) model.Value {
 	return vector
 }
 
-// === hour_of_day(v vector) scalar ===
-func funcHourOfDay(ev *evaluator, args Expressions) model.Value {
+// === hour(v vector) scalar ===
+func funcHour(ev *evaluator, args Expressions) model.Value {
 	vector := ev.evalVector(args[0])
 	for _, el := range vector {
 		el.Metric.Del(model.MetricNameLabel)
@@ -902,8 +902,8 @@ func funcHourOfDay(ev *evaluator, args Expressions) model.Value {
 	return vector
 }
 
-// === month_of_year(v vector) scalar ===
-func funcMonthOfYear(ev *evaluator, args Expressions) model.Value {
+// === month(v vector) scalar ===
+func funcMonth(ev *evaluator, args Expressions) model.Value {
 	vector := ev.evalVector(args[0])
 	for _, el := range vector {
 		el.Metric.Del(model.MetricNameLabel)
@@ -1037,11 +1037,11 @@ var functions = map[string]*Function{
 		ReturnType: model.ValVector,
 		Call:       funcHoltWinters,
 	},
-	"hour_of_day": {
-		Name:       "hour_of_day",
+	"hour": {
+		Name:       "hour",
 		ArgTypes:   []model.ValueType{model.ValVector},
 		ReturnType: model.ValVector,
-		Call:       funcHourOfDay,
+		Call:       funcHour,
 	},
 	"idelta": {
 		Name:       "idelta",
@@ -1097,11 +1097,11 @@ var functions = map[string]*Function{
 		ReturnType: model.ValVector,
 		Call:       funcMinOverTime,
 	},
-	"month_of_year": {
-		Name:       "month_of_year",
+	"month": {
+		Name:       "month",
 		ArgTypes:   []model.ValueType{model.ValVector},
 		ReturnType: model.ValVector,
-		Call:       funcMonthOfYear,
+		Call:       funcMonth,
 	},
 	"predict_linear": {
 		Name:       "predict_linear",
diff --git a/promql/testdata/functions.test b/promql/testdata/functions.test
index 6b1b578c3..731b50898 100644
--- a/promql/testdata/functions.test
+++ b/promql/testdata/functions.test
@@ -370,7 +370,7 @@ clear
 eval instant at 0m year(vector(0))
   {} 1970
 
-eval instant at 0m month_of_year(vector(0))
+eval instant at 0m month(vector(0))
   {} 1
 
 eval instant at 0m day_of_month(vector(0))
@@ -380,7 +380,7 @@ eval instant at 0m day_of_month(vector(0))
 eval instant at 0m day_of_week(vector(0))
   {} 4
 
-eval instant at 0m hour_of_day(vector(0))
+eval instant at 0m hour(vector(0))
   {} 0
 
 # 2008-12-31 23:59:59 just before leap second.
@@ -392,11 +392,11 @@ eval instant at 0m year(vector(1230768000))
   {} 2009
 
 # 2016-02-29 23:59:59 Febuary 29th in leap year.
-eval instant at 0m month_of_year(vector(1456790399)) + day_of_month(vector(1456790399)) / 100
+eval instant at 0m month(vector(1456790399)) + day_of_month(vector(1456790399)) / 100
   {} 2.29
 
 # 2016-03-01 00:00:00 March 1st in leap year.
-eval instant at 0m month_of_year(vector(1456790400)) + day_of_month(vector(1456790400)) / 100
+eval instant at 0m month(vector(1456790400)) + day_of_month(vector(1456790400)) / 100
   {} 3.01
 
 # Febuary 1st 2016 in leap year.