出典:Wiktionary
A collateral form of fortnight with the dialectal change of /xt/ to /θ/ (probably via an intermediate /θt/); compare Doric Scots dother (“daughter”), mith (“might”), and obsolete noth (“nothing”).
Note that drouth (“drought”) is not an example of this change; it instead retains the dental fricative of 古期英語 drugaþ.
fortnith (複数形 fortniths)