There’s a get-together with people from the lab today.
Not many people showed up at today's drinking party and it was also very disorganized, eh?
My younger brother brought his girlfriend to our New Year's gathering.
This is the noun version of the kanji gather, so it means gathering.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading already so you should be able to read it!