city in Maryland, U.S., founded 1729, named for Cecilius Calvert (1605-1675), 2nd baron Baltimore, who held the charter for Maryland colony; from a small port town in southern Ireland where the family had its seat, from Irish Baile na Tighe Mor, literally "townland of the big house." In old baseball slang, a Baltimore chop was a hit right in front of the plate that bounced high.
American microbiologist who discovered the enzyme reverse transcriptase, which is capable of passing information from RNA to DNA. Prior to this discovery, it was assumed that information could flow only from DNA to RNA. He won a 1975 Nobel Prize for his research into the connection between viruses and cancer.