a small band of jazz musicians
"The late-night jazz club featured an intimate combo that kept the crowd dancing until closing time."
A small musical group.
"The local jazz combo opened for the festival, playing smooth tunes that had everyone dancing."
In plain English: A combo is when you combine two or more things into one package to get them all at once.
"The restaurant serves a popular burger and fries combo for lunch."
Usage: Use "combo" to refer informally to a small musical ensemble or band. It is often used in casual conversation when describing a group of musicians performing together, such as at a jazz club or local gig.
The word combo is a clipped form of the phrase combination, with the suffix -o added to make it sound more casual and rhythmic. It entered English as a shortened version used to refer to a mixed meal or a musical group performing together.