Dimictic refers to a type of lake that experiences two major mixing periods each year, one in the spring and one in the fall. Some synonyms for the word dimictic include diphasic, bissextile, and biannual. Diphasic connotes the two phases of mixing that occur in a dimictic lake, while bissextile refers to the two-year intercalation of leap years into the calendar, reminiscent of the duality of dimictic lake mixing. Biannual is a more general term that simply denotes something occurring twice a year, and can be used to describe other phenomena beyond dimictic lake mixing.