gathering spot; hangout; haunt
A place where a particular group of people regularly gather, often with a slightly informal or habitual connotation.
That park has become a hangout for the neighborhood kids.
After school, this café is always our gathering spot.
溜まり場 is the full, explicit word for a gathering spot, while 溜まり is a casual abbreviation of it.
Standard kanji spelling.
Common mixed kana-kanji spelling.
Less common variant with 溜り instead of 溜まり.
Compound of 溜まり (たまり, 'gathering, pooling', nominal form of 溜まる) + 場 (ば, 'place').