Since Open Group does not have a definition, you might have quoted the FEA (http://www.whitehouse.gov/omb/egov/documents/FEA_CRM_v23_Final_Oct_2007.pdf): "Enterprise Architecture is an established process for describing the current state and defining the target state and transition strategy for an organization’s people, processes, and technology."

No worse than Wikipedia's definition, and certainly more authoritative.