late 14c., from Old French annuel (12c.) or directly from Late Latin annualem (nominative annualis), corresponding to Latin annalis as adjective form of annus "year," from PIE *at-no-, from root *at- "to go," on notion of "period gone through" (cf. Sanskrit atati "goes, wanders," Gothic aþnam (dative plural) "year," Oscan akno- "year, holiday, time of offering"). Used of plants since 1710.
c.1400, originally "service commemorating the anniversary of a person's death," from annual (adj.). By 1824 as short for annual plant.
Adjective Completing a life cycle in one growing season.
Noun An annual plant. Annuals germinate, blossom, produce seed, and die in one growing season. They are common in environments with short growing seasons. Most desert plants are annuals, germinating and flowering after rainfall. Many common weeds, wild flowers, garden flowers, and vegetables are annuals. Examples of annuals include tomatoes, corn, wheat, sunflowers, petunias, and zinnias. Compare biennial, perennial.