Source : Webster's Revised Unabridged Dictionary (1913)

Hebdomadal \Heb*dom"a*dal\, Hebdomadary \Heb*dom"a*da*ry\, a.
   [L. hebdomadalis, LL. hebdomadarius: cf. F. hebdomadaire.]
   Consisting of seven days, or occurring at intervals of seven
   days; weekly.

Hebdomadary \Heb*dom"a*da*ry\, n. [LL. hebdomadarius: cf. F.
   hebdomadier.] (R. C. Ch.)
   A member of a chapter or convent, whose week it is to
   officiate in the choir, and perform other services, which, on
   extraordinary occasions, are performed by the superiors.

Source : WordNet®

hebdomadary
     adj : appearing or occurring every seven days; "hebdomadal (or
           weekly) newspapers"; "hebdomadal meetings" [syn: {hebdomadal}]