FAMILIAR - [adjective] known, seen or experienced before; informal, easygoing (familiar style)

Examples of use

Are you familiar with Tennyson's poetry? I think he's a great poet.

Your face seems familiar to me. Have we ever met before?

CUSTOM - [noun] an activity or a ceremony that is a part of living or a culture of some particular group of people

Examples of use

There are many customs on St Andrew's Day, but they vary a lot from country to country.

I cannot understand some ancient tribal customs. They were so brutal.