先週 means 'last week' and is part of the time reference system.
TIME SERIES - WEEKS:
KANJI BREAKDOWN:
- 先: previous, before
- 週: week
SIMILAR WORDS WITH 先:
GRAMMAR NOTES:
- Used as time adverb without particle: 先週会った (I met [them] last week)
- With specific day: 先週の月曜日 (last Monday)
COMMON PATTERNS:
- 先週の末: end of last week
- 先週から: since last week