Leap year

Leap years were a type of year.

Fay proposed to her fiancé Jake Morgan during a leap year. By tradition, he was expected to say no so he would have to buy Fay a silk dress, but he did not understand the tradition and said yes, promising to buy her a silk dress anyway. (PROSE: The Dead Man's Story)

The annual parade of the Church of the Silence, which was held on 29 February, did not take place in leap years. (PROSE: Time Traveller's Diary)