- A diminutive of the male given name Louis.
- A diminutive of the female given names Louisa or Louise; often also used as a middle name.
- (with definite article) A nickname for St. Louis.
- 2000 Nelly, "Country Grammar (Hot Shit"). Country Grammar, Universal Records.
- I'm from the Lou and I'm proud.
- 2006 Anne Tyler, Digging to America, Alfred A. Knopf, →ISBN, page 25:
- Pat and Lou, their names were. The man was Pat and the woman was Lou, or was it the other way around? Maryam knew she was going to have trouble with that.
- A Southeast Admiralty Islands language spoken on Lou Island of Manus Province, Papua New Guinea.
- The Torricelli language of Papua New Guinea.