Here's why:
* Hypothyroidism is a condition, not a specific type of cell or structure.
* Suffixes are typically used to describe specific parts of a word, like "-itis" for inflammation or "-ectomy" for surgical removal.
Instead of a suffix, we use prefixes like "hypo-" to describe the condition:
* Hypo- means "below" or "deficient."
* Thyroid refers to the thyroid gland.
* -ism indicates a condition or state.
Therefore, "hypothyroidism" literally translates to "a condition of deficient thyroid function."