abbreviation of limousine, by 1959, American English.
Entries linking to limo
limousine n.
1902, "enclosed automobile with open driver's seat," from French limousine, from Limousin, region in central France (see Limousine). The automobile meaning is from a perceived similarity of the car's profile to a type of hood worn by the inhabitants of that province. Since 1930s, it has been synonymous in American English with "luxury car." The word was applied from 1959 to vehicles that take people to and from large airports. Limousine liberal first attested 1969 (in reference to New York City Mayor John Lindsay).