1. [n]  a reference book that is published regularly once every year
2. [n]  a plant that completes its entire life cycle within the space of a year
3. [adj]  (botany) completing its life cycle within a year; "a border of annual flowering plants"
4. [adj]  occurring or payable every year; "an annual trip to Paris"; "yearly medical examinations"; "annual (or yearly) income"

ANNUAL is a 6 letter word that starts with A.

1. \An"nu*al\ (?; 135), a. [OE. annuel, F. annuel, fr. L.
   annualis, fr. annus year. Cf. {Annals}.]
   1. Of or pertaining to a year; returning every year; coming
      or happening once in the year; yearly.
            The annual overflowing of the river [Nile]. --Ray.
   2. Performed or accomplished in a year; reckoned by the year;
      as, the annual motion of the earth.
            A thousand pound a year, annual support. --Shak.
   2. Lasting or continuing only one year or one growing season;
      requiring to be renewed every year; as, an annual plant;
      annual tickets. --Bacon.
   

2. \An"nu*al\, n.
   1. A thing happening or returning yearly; esp. a literary
      work published once a year.
   2. Anything, especially a plant, that lasts but one year or
      season; an annual plant.
            Oaths . . . in some sense almost annuals; . . . and
            I myself can remember about forty different sets.
                                                  --Swift.
   3. (R. C. Ch.) A Mass for a deceased person or for some
      special object, said daily for a year or on the
      anniversary day.
   

1. Describes a plant or other organism that completes its whole life cycle in one year
2. Occuring yearly.