suffix

A suffix is the part fixed to the end of a word, and it is the part that tells a reader what kind of thing the word names. The ending -itis marks an inflammation, so a term that closes with it names a condition; -ectomy marks a removal and names a procedure; -ologist marks a person who studies something and names a specialty. Because the suffix carries that job, two terms built on the same root can name quite different things: the root supplies the subject and the ending supplies what is happening to it. A reader who sorts the suffixes into kinds can say whether an unfamiliar term is a disease, an operation or a field of practice before knowing what the root means. When a suffix begins with a vowel, it usually joins straight onto the root with no combining vowel between the two parts.