What does "cash bar" mean?

A bar at a social event where guests are required to pay for their own individual drinks.

Cash bar

noun

noun ·Rare ·Advanced level

Noun

1
A bar at a social event where guests are required to pay for their own individual drinks. US
"The party included a reception, a dance, and a cash bar."
2
a counter at a large party where you can purchase drinks by the glass wordnet

"The party included a reception, a dance, and a cash bar."