Another Bellows innovation was to print all the masculine French headwords in Roman font and the feminine ones in italics. Thus gender information was conveyed instantly, without need to look for an m. or f. label. But how is grammatical gender coded in the lexicon? I notice, for instance, that some French speakers, when asked whether a word is masculine or feminine, reply by associating it with the definite article: la dent, le fleuve. In other cases, words themselves have a ‘flavour’ that informs implicitly: for instance, that a word ending in the sound -sion is feminine.
Le dictionnaire français-anglais de John Bellows (1831-1902)