Of Scottish origin but now widely used in the English-speaking world. It is derived from a topographic term denoting a narrow strait or channel and in part is a transferred use of the surname, a local name from the region in Ayrshire so called. As a girl's name it appears to have been largely superseded by Kyla.
English and Scottish: patronymic from the medieval personal name Nel or Neal, Anglo-Scandinavian forms of the Gaelic name Niall (see Neill). This was adopted by the Scandinavians in the form Njal and was introduced into northern England and East Anglia by them, rather than being taken directly from Gaelic.