I. adjective see: third Date: 14th century recurring at approximately 48-hour intervals, II. noun Date: 14th century a ~ fever (as vivax malaria)
TERTIAN
Meaning of TERTIAN in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012