This document is a description of a proposed activity ontology. It was originally prepared as a submission to the EuroKnowledge [1] standardisation initiative in response to their "Termiknowlogy Request for Action'', and version 1.0 was submitted to them in April 1994. It has subsequently been revised as a result of ongoing discussions, mainly at AIAI, but also in Enterprise project workshops and in the KRSL [2] discussion group of the ARPA/Rome Laboratory Planning Initiative.