noun
3 PM; fifteen o'clock
Used in 24-hour time expressions, common in schedules, transportation, and formal announcements.
会議は１５時からです。
The meeting is from 3 PM.
１５時の新幹線に乗ります。
I'll take the 3 PM Shinkansen.
More common in casual conversation; １５時 is typical in 24-hour clock contexts like timetables.
Compound of 十五 (fifteen) and 時 (hour, o'clock).