| Definition -
A non-active verb that is used to link a sentence's subject to a predicate.
1. All linking verbs are copulas, such as be, appear, become, feel, seem, smell, taste, and sound.
Example - The ice cream tasted good.
(The linking verb tasted describes the subject ice cream.)
However: In He tasted the ice cream, the word tasted is an action verb not a linking verb.
Oxford English Dictionary - The term's first citation is from 1952:
"Adjectives may also be … separated from the nouns they modify by a linking or copulative verb."
(A. H. Marckwardt Introd. Eng. Lang. ii. 115)