Where it's at

where it's at

what does this expression mean??

thanx soo much in advance
ciaoo
Milena

Where the main action (of an activity) is taking place and, thus, metaphorically the supposed centre of almost anything - fashion, music etc. In itself the phrase is almost a fashion item and has only come into the English language within the last 50 years.

It's under the "Hippie Counterculture of the 1960s" in "Flappers 2 Rappers: American Youth Slang" by Tom Dalzell (Merriam-Webster Inc., Springfield, Md., 1996):

where it's at -- The core of what is important or what is happening.