There are various ways in which the singular words are changed into plural numbers in the English language. One of the ways is to add -s at the end of the singular words. With some words -s, -sh, -ch and -es are also added accordingly. There is an exception to this rule when the pluralization of the medical terms are formed. The medical terminology is derived from Greek and Latin, and therefore the rules differ from the basics. When the singular words ending with -a is pluralized, -e is added to the word. The -a is kept and then -e is added. For example, the plural or 'vertebra' will be 'vertebrae'.
