The Collaborative International Dictionary
se'nnight
Sennight \Sen"night\, n. [Contr. fr. sevennight.]
The space of seven nights and days; a week. [Written also
se'nnight.] [Archaic.]
--Shak.
--Tennyson.
Wiktionary
se'nnight
alt. (contraction of sevennight English) n. (contraction of sevennight English)