I. ˈtərshən adjective
Etymology: in sense 1, from Middle English tercian ( fever ) tertian fever, part translation of Latin tertiana febris, from tertiana (feminine of tertianus of the third) + febris fever; from its recurring every third day; in other senses from Latin tertianus of the third, from tertius third + -anus -an — more at third
1. : recurring at approximately 48-hour intervals — used chiefly of vivax malaria; compare quartan
2. : of or relating to a tertiary or to tertianship
3. : relating to the mean tone system of musical temperament in which the major thirds are perfectly in tune
II. noun
( -s )
Etymology: Latin tertianus of the third
1.
[Middle English tercian, from Latin tertiana, from tertiana febris ]
: a tertian fever ; specifically : vivax malaria
2.
[Middle English tercian, from Latin tertianus of the third]
: an old unit of liquid capacity equal to 1/3 tun
3. : a third-year student in arts (as at Aberdeen University)
4. or tertian father usually capitalized T&F : a Jesuit during tertianship
5. : a compound organ stop composed of two ranks of open metal pipes tuned a major third apart