[ gdw]
According to DMF, Gdf and TL this word has two main senses: 1. ‘the action of swimming’ and 2. ‘(fin of) a fish’. In Anglo-Norman, the first sense is found only in the locutions.
The Bibbesworth citation is problematic: Rothwell suggest a link with TL 670: ‘noz de l’eschine = Wirbel des Rückgrats’, in which case this citation would belong under nu1. However, the M.E. gloss sound translates as ‘the swimming bladder of a fish’(see MED sound(e 1), and this sense has been retained here.