Tonight, This Evening
noun
The now night is the current night, aka tonight.
こんや
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
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.