demy

noun
\ də̇mī\
plural -es

Definition of demy

1 : a 15th century gold coin of Scotland weighing from 50 to 53 grains also : a unit of value equivalent to one demy coin a gold half-demy was issued
2 : a scholar on the foundation at Magdalen college, Oxford, originally receiving half the allowance of a fellow
3 : a size of paper commonly 16 × 21, 15¹/₂ × 20, or 17¹/₂ × 22¹/₂ inches