What is the meaning of Glaucus?

Any member of the genus Glaucus of nudibranchiate mollusks, found in the warmer latitudes, swimming in the open sea, strikingly colored with blue and silvery white.

A desert lime (Citrus glauca), a thorny shrub species endemic to semi-arid regions of Australia.

bright, sparkling, gleaming

gray-green, grayish

a bluish-grey colored fish of uncertain identity, perhaps the derbio

Source: wiktionary.org