What does "seatmate" mean?

One who shares a seat (such as a bench or other surface that seats more than one).

What is a synonym for "seatmate"?

Common synonyms include: tablemate.

noun

noun ·Rare ·Advanced level

Noun

1
One who shares a seat (such as a bench or other surface that seats more than one).
2
One who sits next to another.
"My seatmate on the airplane snored incessantly."

"Ziri drove Rima's seatmate away and sat beside her."

From seat + -mate.