The Collaborative International Dictionary of English v.0.48:
Masked \Masked\, a.
1. Wearing a mask or masks; characterized by masks;
2. (Bot.) Same as Personate.
3. (Zool.) Having the anterior part of the head differing
decidedly in color from the rest of the plumage; -- said
Masked ball, a ball in which the dancers wear masks.
Masked battery (Mil.), a battery so placed as not to be
seen by an enemy until it opens fire. --H. L. Scott.
Masked crab (Zool.), a European crab (Corystes
cassivelaunus) with markings on the carapace somewhat
resembling a human face.
Masked pig (Zool.), a Japanese domestic hog (Sus
pliciceps). Its face is deeply furrowed.