Definition of "tertian" [ter•tian]

• Recurring every other day or, when considered inclusively, every third day: a tertian fever. (adjective)
• Pathology A tertian fever, such as vivax malaria. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Cinchona bark had long been used by indigenous people as a remedy for fevers, and at the end of the seventeenth century, a British physician, in one of the earliest controlled studies of a drug, proved that its effect was unique to what was then known as tertian fever."
• "Classically, but infrequently observed, the attacks occur every second day with the "tertian" parasites (P. falciparum, P. vivax, and P. ovale) and every third day with the "quartan" parasite (P. malariae)."
• "Saturday to Tuesday the symptoms continued ever worsening: a kind of tertian ague, "bastard tertian" as the old Doctors name it; for which it was ordered that his"