1. (a.) Happening once in two years; as, a biennial election.
2. (a.) Continuing for two years, and then perishing, as plants which form roots and leaves the first year, and produce fruit the second.
3. (n.) Something which takes place or appears once in two years; esp. a biennial examination.
4. (n.) A plant which exists or lasts for two years.
Thesaurus Entries
amphibian, angiosperm, anniversary, annual, annual holiday, aquatic plant, biannual, bicentenary, bicentennial, bimonthly, birthday, bissextile day, biweekly, catamenial, centenary, centennial, commemoration, cosmopolite, cutting, daily, decennial, deciduous plant, diamond jubilee, dicot, dicotyledon, diurnal, ephemeral, evergreen, exotic, flowering plant, fortnightly, fungus, gametophyte, golden wedding anniversary, gymnosperm, hebdomadal, holy days, hourly, hydrophyte, immovable feast, jubilee, leap year, menstrual, momentary, momently, monocot, monocotyl, monthly, name day, natal day, octennial, perennial, plant, polycot, polycotyl, polycotyledon, quadrennial, quarterly, quasquicentennial, quincentenary, quincentennial, quinquennial, quotidian, secular, seed plant, seedling, semestral, semiannual, semimonthly, semiweekly, semiyearly, septennial, sesquicentennial, sextennial, silver wedding anniversary, spermatophyte, sporophyte, tercentenary, tercentennial, tertian, thallophyte, tricennial, triennial, vascular plant, vegetable, wedding anniversary, weed, weekly, yearly
