To copy or write in a large hand (en gross, i. e., in large); to write a fair copy of in distinct and legible characters; as, to engross a deed or like instrument on parchment.
To purchase either the whole or large quantities of, for the purpose of enhancing the price and making a profit; hence, to take or assume in undue quantity, proportion, or degree; as, to engross commodities in market; to engross power.
A motion to engross a bill is the step before final passage in the house of origin. An order to print a proposal in its engrossed form means to incorporate all amendments and chief clerks corrections to the original bill for consideration by the second house.
Most commonly, the process by which a bill is updated--that is, how adopted amendments and other changes are incorporated into a bill--as it makes its way through the Senate or House.