1.
place, location
A physical location or position.
2.
point, aspect
A particular point in time, or an aspect/characteristic of something.
3.
(at the point of doing)
Used after verbs to indicate timing or circumstances.
I was just about to leave, so I couldn't answer the phone.
～ところ = about to do
所 is a versatile word with multiple uses as a noun and grammar pattern.
USAGE (as noun):
1. Place/location: 静かな所 (a quiet place)
2. Aspect/point: いい所 (good point/trait)
COMMON PATTERNS (after verbs):
- Vる所: about to do (出かける所だ = I'm about to leave)
- Vている所: in the middle of (食べている所です = I'm eating now)
- Vた所: just did (終わった所です = I just finished)
Vる所だった means "was just about to" — often with the sense that it did not happen: 出かける所だった (I was just about to leave).
Similar words
場所 is a concrete, identifiable site — a venue, a seat, a spot on a map. 所 is broader and vaguer: it covers such sites but also parts, aspects, and points in a process. Where both fit, 場所 sounds more specific.
Writing
Written in kanji (所) or hiragana (ところ) depending on usage. Grammar patterns often use hiragana.