n (weightlifting) A weighted disk, usually of metal, with a hole in the center for use with a barbell, dumbbell, or exercise machine.
n (printing|publishing) An illustration in a book, either black and white, or colour, usually on a page of paper of different quality from the text pages.
n (dentistry) A shaped and fitted surface, usually ceramic or metal that fits into the mouth and in which teeth are implanted; a dental plate.
n (engineering|electricity) An electrode such as can be found in an accumulator battery, or in an electrolysis tank.