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Word Roots

Medical terms can be divided into three basic word elements: prefixes, roots (or stems), and suffixes. The root or stem of a medical term usually has been derived from a Greek or Latin noun or verb. This root expresses the basic meaning of the term. However, often that meaning will be modified by the addition of a prefix (at the beginning of the word) or the addition of a suffix (at the end of the word). Frequently a root + a suffix will be used as a suffix and added to another root as a word ending. Some examples are -emia, -genic, -penia, and -pathy. However, two suffixes alone cannot combine to form a word. Three common medical terms, their roots, and their root definitions are listed below.

Medical Term Root Root Definition
tonsillitis tonsilla tonsil (Latin tonsilla)
thermal therm heat
prognosis gno to know

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