Greek:
* Mono-: This is the most common prefix meaning "one" or "single." Examples: monologue, monorail, monocle.
* Uni-: Similar to "mono," but often used in scientific or technical contexts. Examples: unicorn, unilateral, universe.
Latin:
* Uni-: Also used in Latin, with the same meaning as in Greek. Examples: unicameral, unicycle, uniform.
* Singul-: This prefix is less common, but still used sometimes. Examples: singular, singularity.
Other:
* Semi-: While not strictly meaning "one," this prefix can sometimes indicate a single or half. Examples: semicircle, semiannual.
* Sol-: This prefix comes from the Latin word "sol," meaning "sun," and can be used to signify singularity or uniqueness. Examples: solitary, solstice.
Remember that the choice of prefix depends on the context and the specific word you are creating.