AMBULATORY is a 10 letter word that starts with A.

1. \Am"bu*la*to*ry\, a. [L. ambulatorius.]
   1. Of or pertaining to walking; having the faculty of
      walking; formed or fitted for walking; as, an ambulatory
      animal.
   2. Accustomed to move from place to place; not stationary;
      movable; as, an ambulatory court, which exercises its
      jurisdiction in different places.
            The priesthood . . . before was very ambulatory, and
            dispersed into all families.          --Jer. Taylor.
   3. Pertaining to a walk. [R.]
            The princess of whom his majesty had an ambulatory
            view in his travels.                  --Sir H.
                                                  Wotton.
   4. (Law) Not yet fixed legally, or settled past alteration;
      alterable; as, the dispositions of a will are ambulatory
      until the death of the testator.
   

2. \Am"bu*la*to*ry\, n.; pl. {Ambulatories}. [Cf. LL.
   ambulatorium.] (Arch.)
   A place to walk in, whether in the open air, as the gallery
   of a cloister, or within a building.