Answer: False
T-cells get their name from the endocrine gland (thymus) in which they are stored, not from the thyroid gland.
T cells belong to a subtype of white blood cells known as "lymphocytes", that is why T cell are also known as T lymphocytes. The "T" stands for "thymus" -- the small endocrine gland in which these cells mature. It is responsible for a variety of other immune responses.