Longman Dictionary of Contemporary English
table manners
noun
EXAMPLES FROM CORPUS
▪ Are they conventional rules that we learn as we learn, say, table manners?
▪ Good table manners, I submit, are largely overrated.
▪ Perdita thought, to take an example at random, that things like table manners were a stupid and repressive idea.
▪ Since dress, gait and table manners instantly distinguish social rank, all over the world, why not speech as well?
▪ Their table manners perfectly reflect the slovenly appearance.
Wiktionary
table manners
n. 1 An accept code of conduct for behaviour at a dine table. 2 The manner of a behavior of an individual while dining.