SiredonSi*re"don\, n. [NL., from Gr. ??? a siren.] (Zo["o]l.) The larval form of any salamander while it still has external gills; especially, one of those which, like the axolotl (Amblystoma Mexicanum), sometimes lay eggs while in this larval state, but which under more favorable conditions lose their gills and become normal salamanders. See also Axolotl.