(computer science) A set of items, records, or documents to be processed as a single unit.
(engineering) The quantity of material required for or produced by one operation. An amount of material subjected to some unit chemical process or physical mixing process to make the final product substantially uniform.
(petroleum engineering) In a pipeline operation, a volume of a crude oil of a given density that is pumped next to one of a different density to help prevent mixing of deliveries.

McGraw-Hill Dictionary of Scientific and Technical Terms. Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-Hill Companies, Inc. All rights reserved.