A communication by a supplier to advise a purchaser that a purchase order has been received. It usually implies acceptance of the order by the supplier.
Acquisition Cost: In cost accounting, the cost required to obtain one or more units of an item. It is order quantity times unit cost.
Action Message: An alert that an MRP or DRP system generates to inform the controller of a situation requiring his or her attention.
Active Stock: Goods in active pick locations and ready for order filling.
Activity: Work performed by people, equipment, technologies, or facilities. Activities are usually described by the action-verb-adjective-noun grammar convention. Activities may occur in a linked sequence and activity-to-activity assignments may exist.
1.
In activity-based cost accounting, a task or activity, performed by or at a resource, required in producing the organization's output of goods and services. A resource may be a person, machine, or facility. Activities are grouped into pools by type of activity and allocated to products.
2.
In project management, an element of work on a project. It usually has an anticipated duration, anticipated cost, and expected resource requirements. Sometimes major activity is used for larger bodies of work.
Activity Analysis: The process of identifying and cataloging activities for detailed understanding and documentation of their characteristics. An activity analysis is accomplished by means of interviews, group sessions, questionnaires, observations, and reviews of physical records of work.

This definition is in context to Supply Chain. See more contextual defintions for Acknowledgement.