Acquaintance
Definition 1 of 3
Pro Tip 1/3
Social distance
Indicates you recognize and sometimes interact with the person, but lack a close bond. At the conference, I chatted with a few acquaintances over coffee.
Pro Tip 2/3
Frequency of contact
Can be used for someone you meet occasionally or rarely, rather than regularly. My acquaintance from yoga class and I bumped into each other at the mall.
Pro Tip 3/3
No personal details
You typically don't know personal details about an acquaintance, unlike a friend. Even though I see him at events, he's more of an acquaintance; I don't know much about him.