Лингвистические случайности? CLNDR

Не однокоренные: Cylinder, Calendar.

A cylinder (from Greek κύλινδρος - kulindros, "roller, tumbler").

Kalendae (whence "calendar"), Kalends—first day of the month. It is thought to have originally been the day of the new moon. The word is from the Greek καλέω, i.e. announce.