Meaning of shadow mask

shad'ow mask"

Pronunciation: [key]
— Television. Television.
  1. a perforated metal plate situated behind the faceplate of a color television picture tube and having holes aligned to insure that each of three electron beams strikes only its corresponding red, green, or blue phosphor dot. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.