is a specific kind of: diapsid, diapsid reptile.

is a broader term that covers: colubrid, colubrid snake | blind snake, worm snake | constrictor | elapid, elapid snake | sea snake | viper.

is a member of: Ophidia, Serpentes, suborder Ophidia, suborder Serpentes.

derivation: serpentine, snakelike, snaky.