noun
acquaintance
uh-KWAYN-tuns/əˈkweɪntəns/
Familiarity gained through limited personal contact.
Their slight acquaintance is enough for a friendly wave as they pass.

Etymology
The pieces describe the state of knowing someone. This abstract sense of familiarity was then applied to the person known, providing the bridge to today's meaning of someone known but not closely.
In context
apologize to the other for so doing whether he is an acquaintance or a stranger
More examples
- An old acquaintance waves to me from the café.
- The class assumes no prior acquaintance with computer programming.
- We remain friendly acquaintances rather than close friends.
Forms
acquaintance · acquaintances
acquaint verb — To make someone familiar with something.
Similar words
- familiarity
- Can imply deeper experience than limited personal contact.
- friend
- Usually names someone with a closer personal relationship.