noun
clock, o''clock
A1
Uhr (die) primarily means 'clock' and, in time expressions, 'o'clock' (Es ist drei Uhr). It’s a feminine noun with plural Uhren. Used with numerals (zwei Uhr) usually without an article in time phrases. For a wristwatch say Armbanduhr or die Uhr. Declines regularly.
Examples
Wie viel Uhr ist es?
What time is it?
Es ist drei Uhr.
It's three o'clock.
Die Veranstaltung begann um zwölf Uhr, weil viele Gäste früher ankamen.
The event started at twelve o'clock because many guests arrived earlier.
Details
Mnemonics
a round clock face with 'U' shaped hands
sounds like 'your' — your watch (think 'your clock')
die Uhr — imagine a lady wearing a watch (die for feminine)
Notes
Uhr is used both to mean a clock/watch and to express time (e.g., 'drei Uhr').