mask vs overlay

mask

noun
  • A flat covering used to block off an unwanted portion of a scene or image. 

  • The mesh of a net; a net; net-bag. 

  • A cover, or partial cover, for the face, used for disguise or protection. 

  • That which disguises; a pretext or subterfuge. 

  • A person wearing a mask. 

  • A pattern of bits used in bitwise operations; bitmask. 

  • A two-color (black and white) bitmap generated from an image, used to create transparency in the image. 

  • mesh 

  • The lower lip of the larva of a dragonfly, modified so as to form a prehensile organ. 

  • In a permanent fortification, a redoubt which protects the caponiere. 

  • A festive entertainment of dancing or other diversions, where all wear masks; a masquerade. 

  • Mash. 

  • The head of a fox, shown face-on and cut off immediately behind the ears. 

  • A social phenomenon where autistic people learn, practice, and perform certain behaviors and suppress others in order to appear more neurotypical. 

  • A grotesque head or face, used to adorn keystones and other prominent parts, to spout water in fountains, and the like. 

  • A screen for a battery. 

verb
  • To set or unset (certain bits, or binary digits, within a value) by means of a bitmask. 

  • To bewilder; confuse. 

  • To conceal from view or knowledge; to cover; to hide. 

  • To conceal or disguise one's autism. 

  • To prepare tea in a teapot; alternative to brew. 

  • To disable (an interrupt, etc.) by setting or unsetting the associated bit. 

  • To cover (the face or something else), in order to conceal the identity or protect against injury; to cover with a mask or visor. 

  • To conceal; also, to intervene in the line of. 

  • (brewing) To mix malt with hot water to yield wort. 

  • To take part as a masker in a masquerade. 

  • to cover or shield a part of a design or picture in order to prevent reproduction or to safeguard the surface from the colors used when working with an air brush or painting 

  • To mash. 

  • To disguise as something else. 

  • To cover or keep in check. 

  • To wear a mask. 

  • To be infused or steeped. 

overlay

noun
  • A covering over something else. 

  • A block of program code that is loaded over something previously loaded, so as to replace the functionality. 

  • A decal attached to a computer keyboard to relabel the keys. 

  • A pop-up covering an existing part of the display. 

  • A horse going off at higher odds than it appears to warrant, based on its past performances. 

  • A piece of paper pasted upon the tympan sheet to improve the impression by making it stronger at a particular place. 

  • A cravat. 

  • Odds which are set higher than expected or warranted. Favorable odds. 

verb
  • To lay, spread, or apply something over or across; cover. 

  • To put an overlay on. 

  • simple past tense of overlie 

  • To overwhelm; to press excessively upon. 

  • To bet too much money on. 

How often have the words mask and overlay occurred in a corpus of books? (source: Google Ngram Viewer )