Once a year, every year

adjective

1. Covering the period of a year

   "annual rainfall"

2. Occurring or happening every year or once a year yearly

   "an annual reunion"

3. Completing the life cycle in one growing season or single year

   "annual plants"

noun

1. An event that occurs yearly
2. A publication appearing yearly

   "the high-school annual"

3. Something that lasts one year or season

noun

1. A usually lengthy report issued yearly by an organization giving an account of its internal workings and especially its finances

noun

1. The layer of wood produced by a single year's growth of a woody plant

noun

1. An annual salary increase

   "Employees receive an annual increment of three percent."

adjective

1. Occurring between, relating to, or involving two or more years occurring or observed in different years

   "interannual changes in weather patterns"