unison
unisexs
Universal.
universe
uni word means to sing together as one
uni
The prefix "uni-" in the word unicellular means one or single. Therefore, unicellular refers to an organism or structure consisting of a single cell.
Uni or mono.
Unique.
The word you are looking for is "unite." It comes from the Latin root "uni," meaning "one."
The affix in the word uniform(s) is uni- which is in Latin unus, una and unum. Unus, una and unum means one in Latin! Uni- means one/singular.
The prefix "mono" means "one", as in "monotheism" - belief in one God; "monotone" - one tone (either musical or colour); from the Greek "monos" - alone. The prefix "uni" also means "one" as in "unicycle" - a one-wheeled vehicle; "unicorn" a one-horned mythical beast; from the Latin "unus" - one.