Wiktionary
boothmate
n. One who shares the same booth.
Usage examples of "boothmate".
Khorrl asked, baiting his boothmate to see what his reaction would be.
He did not look up as I slipped into the bench across from him, but the lizard waiter slithered up and I pointed to the drinker, then raised a finger, ordering a return for my unknown boothmate.