Final answer:
Using the term 'thyr/o' combined with '-megaly', which implies enlargement, we form the word 'thyromegaly', meaning an enlarged thyroid gland.
Step-by-step explanation:
The term you are searching for that expresses the enlargement of the thyroid gland using the root 'thyr/o', is thyromegaly. The prefix 'thyro-' refers to the thyroid. Meanwhile, the suffix '-megaly' signifies enlargement. As such, together, 'thyromegaly' means an enlarged thyroid gland, a condition that can occur due to various thyroid disorders like Hashimoto's disease, Graves' disease, or thyroid nodules.
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