SENNIGHT, noun sen'nit. [contracted from sevennight, as fortnight from fourteennight.] The space of seven nights and days; a week. The court will be held this sennight, that is, a week from this day; or the court will be held next Tuesday sennight, a week from next Tuesday.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI