adjective
Happening every day; daily.
Having the characteristics of something which can be seen, experienced, etc, every day or very commonly.
(medicine) Recurring every twenty-four hours or (more generally) daily (of symptoms, etc).
Something which is considered humdrum or dull.
noun
(medicine, now rare, historical) A fever which recurs every day; quotidian malaria.
(Anglicanism, historical) A daily allowance formerly paid to certain members of the clergy.
(usually with definite article) Commonplace or mundane things regarded as a class.