Dennis
DEN-iss
A long-established name meaning “follower of Dionysus,” the Greek god of wine and festivity.
Meaning
Dennis is a form of Dionysius, ultimately from Greek Dionysos/Dionysius. In the excerpts, it is glossed as derived from Dionysos and also noted as an Anglo-Norman/English form of that name; one source also notes that Denis could be used in Ireland as a substitute for Donogh. The core etymological sense is therefore tied to Dionysus rather than to the modern English word "dennis" or any native English root.
Origin
GreekLatinOld FrenchEnglishmasculine
Fun fact
19th-century name books note several historical spellings and relatives of Dennis, including Denis, Denys, Dennet, and even Irish use as a substitute for Donogh.
Confidence: mixed. Sources: History of Christian Names, Praenomina; or, the etymology of the principal Christian names of Great Britain and Ireland.