The Other Day
A Few Days Ago, Other Day
The previous day isn't necessarily yesterday. It can be any recent day, which is why this word means the other day.
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 日 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
The other day, you saw two centaurs! Gee, two (せんじつ) of them?! You're lucky you're still alive!
what happened the other day
news from the other day
comments from the other day
Thank you so much for the other day.
The party the other day got canceled.
Did you like my idea from the other day?