Emily Dickinson Lexicon

GRIST, n. [Sax. grist; Eth. ሐረጸ charats, to grind, coinciding with Heb. and Ch. חרץ. Class Rd, No. 60, 58, &c.]

1. Properly, that which is ground; hence, corn ground; but in common usage, it signifies corn for grinding, or that which is ground at one time; as much grain as is carried to the mill at one time, or the meal it produces. Get grist to the mill to hare plenty in store. Tusser.
2. Supply; provision. Swift.
3. Profit; gain. [as in Latin emolumentum, from molo, to grind.] in the phrase, it brings grist to the mill.