Ex:
Tilton, Rita S., et al. The Electronic Office: Procedures & Administration. 11th ed. Cincinnati: South-Western Publishing Co., 1996
I just had to type this is a class.
In layman's terms it means 'and others' or 'and colleagues' etc... Basically if a team is responsible for something but there is one lead guy then they'll mention him and say "et al." for the rest. You'll see it a lot in academic and scientific references.
Thanks.
Happy ending.