Webster's Revised Unabridged Dictionary · 1913

Demy

Demy , noun

[See Demi-.]

1.
A printing and a writing paper of particular sizes. See under Paper.
2.
A half fellow at Magdalen College, Oxford.
He was elected into Magdalen College as a demy; a term by which that society denominates those elsewhere called “scholars,” young men who partake of the founder's benefaction, and succeed in their order to vacant fellowships. — Johnson

Demy , adjective

Pertaining to, or made of, the size of paper called demy; as, a demy book.