The hour (common symbol h) is a unit of w:time. It is not an w:SI unit but is accepted for use with the SI.
In modern usage, an hour is a w:unit of measurement of w:time of the duration of 60 minutes, or 3600 seconds. It is 1/24 of a median Earth day.
24 Hour Clock
Book of Hours detail
Neon Internet Cafe open 24 hours
Hours of Service
Hours and planets