sennit Syllabification: (sen·nit)Pronunciation: /ˈsenit/ (also sinnet)Definition of sennit noun plaited straw, hemp, or similar fibrous material used in making hats. Nautical braided cordage in flat, round, or square form, used for making mats, lashings, etc.. Origin: early 17th century: of unknown originsennit in other Oxford dictionaries Definition of sennit in the British & World English dictionary