At first sight, a surprising unique attestation in Anglo-Norman, of a word that only appears in English in the eighteenth century (see OED) and in French in the first half of the nineteenth century (see TLF), in both cases originating from a scientific context. However, as the DMLBS shows, the word is common both in classical and in medieval Latin, specifically with the meaning of ‘edible kernel of nut’. In other words, it is rather surprising that the word has no further attestations in the medieval vernaculars.

Alternatively, because of its apparent rarity, and because of the somewhat dubious quality of the transcriptions in Five Med MSS it may be that the word is a misreading here. Without having access to the manuscript, it can only be suggested that a possible alternative reading of the word may be nueleauns, in which case it could be interpreted as a variant of nueillon.