せんじつ先日senjitsu
1.
A day that is not too far in the past, often referenced as a recent occasion or event that occurred a short while ago.
2.
An unspecified day that falls somewhere between the immediate past and yesterday, typically used to indicate a moment recently experienced or noted.
3.
A past day that is more recent than yesterday, which can refer to events or interactions that have taken place in the near past.
Example:
先日小学校のクラス会に出席した。