The poet is using a metaphor. Your answer is correct.
Answer:
the vowel that joins a root to another root or to a suffix
Explanation:
My/o as in Myology employs a combining vowel, in this case, the 'o', which serves as a merger for two root words or a root word and a suffix. Known to have no distinct meaning, this vowel eases the pronunciation of certain medical terms that are otherwise difficult to pronounce.
Another example is cardiology, which is the study of the heart and diseases associated with it. Cardia is a root word in Greek which means 'heart', and logy is another root wordy in Greek which refers to the 'study of'. It is widely used for this purpose and is seconded by the combining vowel 'a'.
