A coupon book or book of tickets sold in sets for multiple rides, usually cheaper than buying single tickets.
電車の回数券は一枚ずつ買うより安い。
A book of train tickets is cheaper than buying single tickets.
学生は通学用に回数券を買っている。
Students buy ticket books for their commute.
この駅は回数券の自動販売機が撤去された。
The vending machine for ticket books at this station was removed.