Is a glass snake a kind of lizard?

Lizards have ear slits and eyelids. Snakes do not. Glass lizards, while having no feet, do have ear slits and eyelids. That makes them a lizard rather than a snake.

Not all lizards have ear slits (genus cophosaurus). Not all lizards have eyelids (infraorder gekkota excluding the genus eublepharinae). Glass lizards, however, have both these parts.