Definition of "quarter-plate" []

• In photography: A size of plate measuring 3¼ × 4¼ inches. The half-plate measures 4¼ × 5½ inches in the United States (4¾ × 6½ in England), and the whole-plate 6½ × 8⅓ inches. (noun)
• A plate of this size, or a picture made from such a plate. (noun)

The Century Dictionary (Public Domain)

• "The vegetables and grains sections of the plate both are slightly larger than a quarter-plate, and fruit and protein sections are a bit smaller."
• "A focal length of about six inches will be best for a quarter-plate camera."
• "As regards the size of the outfit, quarter-plate (3 1/4 x 4 1/4 inches) will usually be found to be large enough for the traveller."