[ seet-meyt ]
/ ˈsitˌmeɪt /


a person who shares a seat or occupies the seat next to oneself on a bus, plane, etc.

Origin of seatmate

An Americanism dating back to 1855–60; seat + mate1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for seatmate