1
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Phrase(s): where it’s at
Sl. what one is aiming for; what is needed. (This does not refer to a place.) • Keep on trying. That’s where it’s at! • Good strong friends. That’s where it’s at.
McGrawhill's American Idioms And Phrasal Verbs
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general::
Also, where the action is. The key center of activity; where important things are happening. For example, He decided to set up his store here, convinced that this is where it's at, or I'm going into the brokerage business; that's where the action is these days. The action or activity in this phrase can relate to just about anything? financial, political, social, or commercial. [Slang; c. 1960]
American Heritage Idioms