noun, noun which may take the genitive case particle 'no'
class period; school period
Specifically a scheduled class period in a school timetable. Often used with numbers: 1時限目, 2時限目, etc.
1時限目は数学です。
The first period is math.
時限ごとに教室が変わる。
The classroom changes each period.
noun, noun which may take the genitive case particle 'no'
time period; time limit
Broader sense of a fixed division of time or a deadline. Less common than the school-period sense; often seen in formal or technical contexts.
この作業には時限が設けられている。
A time limit has been set for this task.