What's the difference between a thyroid nodule and a tumor?

Terminology: A nodule is a non-specific term for any mass or abnormal tissue, it may be due to inflammation, part of goiter or could be a tumor. The tumor usually indicates a cancerous lesion, though benign tumors are also called tumors.

Thyroid tumor: "tumor" from a medical perspective simply means an abnormal growth. So by definition any thyroid nodule is a tumor. What is of significance is whether or not it is a cancer. This is most easily assessed with a fine needle aspiration biopsy or "fna". Although not 100% accurate it can give your doctor a better understanding of what it is and what should be done next.