Etymology: OE. íʒʒað, íʒeoð was perh. a dim. of íeʒ, íʒ, island (though the ordinary power of -að was to make abstr. nouns, as in huntað hunting).
The subsequent phonetic history is obscure: the normal descendant of íʒʒað would be ieth (cf. flieth); the vowel of ME. eyt might arise from an OE. variant éʒað, as in éʒ isle for íʒ (cf. also ONor. eið ‘peninsula,’ in Shetland eid ‘a tongue of land’); but the t is unexplained; the later -et, and mod. -ot, are artificial spellings after islet (MFr. islette) and mod.Fr. îlot.