Umm (أم)

(1) Umm means Mother or 'Mother of ...'. For example, 'Umm Ahmed' means Mother of Ahmed. In Arab countries most people are called Umm X, (where X is the name of the first son or daughter,) by people who know them, instead of their official name.
(2) Umm can also mean 'possessor of X', where X can be an attribute or a distinct object. For example the name Umm Kulthoom means 'Possessor of chubby cheeks'.

Also of interest to you may be the word Abu.

Umm Kulthoom was the nickname of one of the daughters of Imam Ali (AS), the Prophet Muhammed's (SAW) cousin.

» Islamic Glossary