tertian

Meanings

1. Characterised by paroxysms recurring every other day (that is, every third day by inclusive reckoning).
2. Pertaining to the mean-tone temperament, in which major thirds are perfectly in tune.

1. A tertian fever.
2. A cask of a certain size; its volume used as a measure of capacity (one-third of a tun's).
3. A Jesuit going through tertianship.

Etymology

From Middle English tertiān, terciān, terciāne (adjective and noun), originally often as part of the collocation fever cum terciane, after Latin febris cum tertiānā. Compare the "third" essence of tertiary. By surface analysis, terti- + -an.