noun
number of long, cylindrical things; count of items counted with 本
Used for the count of objects typically counted with the counter 本 (ほん), such as pencils, bottles, trains, movies, and home runs. Not a general word for 'number'.
See also: 本
この箱に入っている鉛筆の本数を数えてください。
Please count the number of pencils in this box.
一日に運行する電車の本数は多い。
The number of trains running per day is large.