Based on the definition of communication that Griffin presents and explains, what single word in that definition provides the best synonym or functional equivalent for the term communication?

The single word is "messages": the single word that provides the best synonym or functional equivalent for the term communication is "messages".

Explanation:

Based on Griffin's definition, communication is the relational process of creating and interpreting messages that elicit a response; in this definition, the word "messages "provides the best synonym for the term "communication ". Generally, theorists use the word "communication" as a synonym for a message.