What is the meaning of Petit-gris?

a Eurasian red squirrel (Sciurus vulgaris), which in colder areas (i.e. Russia whence fur has been imported) has more gray or white fur (and therefore has also been called Sciurus cinereus)

a gray squirrel (Sciurus griseus)

a Siberian chipmunk (Tamias sibiricus)

fur of any such animal

a paintbrush from such a fur

a garden snail (Cornu aspersum, syn. Helix aspersa)

a grey knight or dirty tricholoma, a mushroom of species Tricholoma terreum (syn. Tricholoma myomyces)

, a certain cultivar of melon

a gray feather obtained from a female ostrich under her venter

fur of the animals signified above in the French section

Source: wiktionary.org