Hebdomad

from WordNet (r) 3.0 (2006)

hebdomad
    n 1: any period of seven consecutive days; "it rained for a
         week" [syn: {week}, {hebdomad}]

from The Collaborative International Dictionary of English v.0.48

Hebdomad \Heb"do*mad\, n. [L. hebdomas, -adis, Gr. "ebdoma`s the
   number seven days, fr. ? seventh, ? seven. See {Seven}.]
   A week; a period of seven days. [R.] --Sir T. Browne.
   Hebdomadal