Green’s Dictionary of Slang

combo n.2

[abbr. SE combination + -o sfx (6)]

1. a partnership, esp. a group of musicians.

[US]Metronome May 28: As a soft fiddle-sax combo, it clicks.
[US]Music Library Association Notes Dec. 41: Combo: abbrev. of ‘combination.’ Refers generally to an instrumental group usually smaller than a band.
[US]L. Durst Jives of Dr. Hepcat (1989) 5: Just as soon as the canary pulls her number, the combo breaks out like the measles and presses much ether.
[US]Mad mag. Sept. 41: A hot combo of the hipsters, by the hipsters and for the hipsters shall not cut out.
[UK]T. Keyes All Night Stand 94: These Yank airforce combos they have, they get me to sit in.
[US]D. Jenkins Semi-Tough 156: Those who didn’t mind leaving other parts of the lawn where the rock combos were playing.
[UK]Time Out 10–16 Dec. n.p.: His self-styled punk rock combo [KH].
[Aus]R.G. Barrett White Shoes 110: A two-piece combo warbling some old Hall and Oates song.
[UK]N. Cohn Yes We have No 297: A combo is playing swing on the bandstand.
[UK]Observer Screen 16 Jan. 24: I rented a top-floor flat from an elderly brother-and-sister combo.

2. (UK/US Und.) a combination lock (on a safe).

[US]AS ‘Und. Argot’ Dec. 107: combo: combination of a safe.
[US]J.M. Cain Moth (1950) 174: My fingers kept working the combo.
[US]E. De Roo Young Wolves 71: You got my combo out of Chief’s office, didn’t ya?
[US]S. King Finders Keepers (2016) 7: ‘Now the combo,’ said Mr Blue. ‘He snapped his gloved fingers. Give it up’.

3. (US) any form of combination, whether of people, things, sandwich ingredients, wagers etc.

[US]Ersine Und. and Prison Sl. 28: combo, n. The ingredients of a meal, ready for cooking; a meal.
[US](con. 1920s) ‘Harry Grey’ Hoods (1953) 265: ‘The Combo taking the union over?’ Lefty asked.
[US]E. De Roo Young Wolves 106: I got a winning combo and I want to keep it that way.
L. M. Ackerman ‘Miscellany’ in AS XXXVII:1 79: A food combination may now be called a combo, as in the following examples: ‘Potluck Supper on Slate? Take chicken-rice combo’.
[US] Letter in Edelman Dear America (1985) 8 Feb. 153: That cozy spot known as the ‘Pink Pussycat,’ a combo bachelor officer quarters and social club.
[UK]A. Bennett Habeus Corpus Act I: I think they’ve clicked, Scorpio and Sagittarius. Lovely combo.
[US]J. Ellroy Brown’s Requiem 150: To the right of the living room was a kiddie-room-sewing-room combo.
[UK]J. Mowry Way Past Cool 100: The combo of beer and the cops on top of confronting the gang of young boys had stretched even his patience thin.
[UK]Observer Mag. 25 July 23: With the pills, it was an unbelievable combo. Plus the crazy men.
[US]J. Ridley Conversation with the Mann 89: Men and men were routine, same with women and women, and men and men who dressed like women, and any other combo you could dream up.
[UK]J.J. Connolly Viva La Madness 290: Morty is driving and he’s livid, not a good combo.
[US]C. Rhatigan ‘October 17 ... Meeting’ in Pulp Ink [ebook] I need fire running through my veins for this. Instead I’ve got a combo of caffeine, nicotine and dexedrine.

4. a relationship.

[UK]C. MacInnes Absolute Beginners 60: You ever had that combo [i.e. a loving relationship].

5. (US campus) a bisexual person.

[US](con. 1960s) M. Kingston Tripmaster Monkey 78: Pseudo psycho lesbo sappho weirdo hetero homo combos.