(2) Abu can also mean 'possessor of X', where X can be an attribute or a distinct object. For example the name Abu Huraira means 'Possessor of Cats'.
Also of interest to you may be the word Umm.
Abu Huraira (RA) is one of the most well known Hadith transmitters and Sahabah. He has transmitted an incredible number of hadiths.