What does "eat out" mean?

Have a meal outside one's home, usually at a restaurant. For example, We're almost out of groceries, so let's eat out tonight. [Second half of 1900s] For the antonym, see eat in.

eat someone out Also, eat someone up. Rebuke or scold someone sharply, as in He was always eating out the kids, or Why are you eating me up? I haven't done anything wrong. This slangy synonym for chew out probably originated as a euphemism for eat someone's ass out. It dates from the 1940s, the variant from the 1840s. Also see the subsequent entries beginning with eat out.