diff --git a/bar.go b/bar.go
index c05ec42..f18ef96 100644
--- a/bar.go
+++ b/bar.go
@@ -15,7 +15,7 @@
 	"github.com/vbauerster/mpb/v6/decor"
 )
 
-// Bar represents a progress Bar.
+// Bar represents a progress bar.
 type Bar struct {
 	priority int // used by heap
 	index    int // used by heap
@@ -44,6 +44,8 @@
 
 type extenderFunc func(in io.Reader, reqWidth int, st decor.Statistics) (out io.Reader, lines int)
 
+// bState is actual bar state. It gets passed to *Bar.serve(...) monitor
+// goroutine.
 type bState struct {
 	id                int
 	priority          int
diff --git a/progress.go b/progress.go
index c53430d..5a3f962 100644
--- a/progress.go
+++ b/progress.go
@@ -22,7 +22,8 @@
 	prr = 120 * time.Millisecond
 )
 
-// Progress represents the container that renders Progress bars
+// Progress represents a container that renders one or more progress
+// bars.
 type Progress struct {
 	ctx          context.Context
 	uwg          *sync.WaitGroup
@@ -35,6 +36,8 @@
 	dlogger      *log.Logger
 }
 
+// pState holds bars in its priorityQueue. It gets passed to
+// *Progress.serve(...) monitor goroutine.
 type pState struct {
 	bHeap            priorityQueue
 	heapUpdated      bool
@@ -172,7 +175,7 @@
 	p.setBarPriority(b, priority)
 }
 
-// BarCount returns bars count
+// BarCount returns bars count.
 func (p *Progress) BarCount() int {
 	result := make(chan int, 1)
 	select {