Action Verb: When "defined" describes a specific action, it is an action verb.
* Example: The architect defined the boundaries of the property. (The architect took a specific action - defining the boundaries.)
Linking Verb: When "defined" connects the subject to a noun or adjective that renames or describes the subject, it is a linking verb.
* Example: The architect's vision defined the project's unique style. (The verb "defined" connects the subject "vision" to the noun "style," which renames it.)
To determine whether "defined" is an action verb or a linking verb, look at the words that follow it. If they describe an action, it's an action verb. If they rename or describe the subject, it's a linking verb.