Final answer:
In George Herbert's "Coloss. 3.3", the wordplay involving 'Son' and 'sun' is a pun that uses the homophonic qualities of the two words to convey layered meanings.
Step-by-step explanation:
The wordplay involving the words Son and sun in "Coloss. 3.3" by George Herbert is indeed an example of a pun. A pun is a form of wordplay that exploits multiple meanings of a term, or similar-sounding words, for an intended humorous or rhetorical effect. When George Herbert uses this technique, he is playing on the homophonic relationship between 'Son' referring to Jesus Christ and 'sun' as in the star at the center of our solar system, creating layers of meaning in his religious poetry.