Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
cognomen is a noun meaning "a familiar name for a person (often a shortened version of a person's given name)". It carries 2 recorded senses.
a familiar name for a person (often a shortened version of a person's given name)
“Joe's mother would not use his nickname and always called him Joseph”
“Henry's nickname was Slim”
the name used to identify the members of a family (as distinguished from each member's given name)
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for cognomen come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.