Clientele is all the customers of a business taken together. A wealthy clientele, build a clientele, the usual clientele.
It is a collective noun and takes a singular verb, so a clientele is rather than are. It carries a faint suggestion of a particular sort of customer, which is why a bar has one and a supermarket does not.
1nounclienteleAll the customers of a business taken together.
“The café's clientele is mostly students and young families.”
clientele is a customers.
French clientele comes from Latin cliens, a dependant or follower.
Proto-Indo-European
*ḱlew-
Latin
cliēns
French
clientèle
English, today
clientele
French clientèle, ultimately from Latin cliēns (English client).
Etymology from Wiktionary, CC BY-SA