Tonight
This Evening
noun
The now night is the current night, aka tonight.
This is a jukugo word, which usually means on'yomi readings from the kanji. You haven't learned the on'yomi reading for 夜 yet, so here's a mnemonic:
Tonight, you're going to a Yankees (や) baseball game. Not just any game, not just any night — the Yankees, tonight.
ウェディングパーティーは今夜です。
The wedding party is tonight.
今夜は一人でジムに行きます。
I will go to the gym alone tonight.
今夜は西の方に水星が見えるかもしれません。
You may see Mercury in the west tonight.