Domino mask

Promotional art by Darwyn Cooke for DC Comics' The Spirit, who wears a domino mask.

A domino mask is a small, rounded mask covering only the eyes and the space between them. Since the 18th century, the domino mask is worn during carnival, especially in Venice, where its origin lies. In comic book and popular culture, a domino mask indicates that a superhero/heroine wishes to maintain his/her secret identity; at the same time the mask actually obscures little of the facial features that make the character recognizable. For example, Batman's sidekick Robin and the Lone Ranger wear a domino mask. A domino mask is very similar to a masquerade mask, except it is not as embellished or decorated.
The original designs for Batman utilised a simple domino mask as part of his disguise, but Batman co-creator Bill Finger suggested that Bob Kane give him a cape and cowl instead.