plus-one

or plus one

[ pluhs-wuhn ]

noun

1. a person who accompanies someone to a party or other event when the invitation allows the invited guest to bring another person:

   I phoned Tom to ask if he would be my plus-one at the gala.

plus-one

noun

1. informal.
   a person who accompanies an invited person to a social function

Word History and Origins

Origin of plus-one¹

First recorded in 1970–75

Example Sentences

The length should be the headsize measurement plus one-half inch.

From Project Gutenberg