Look up a word in an authoritative dictionary or online (see References). For example, you look up the word "semicircle" in "Webster's New World Dictionary of the American Language, College Edition."
Look for the square brackets following the word and the information within the brackets. For example, after "semicircle" you find "[L. semicirculus; see
SEMI- + CIRCLE]."
Look up any abbreviations you don't understand in the front of the dictionary. For example, the "L." in the square brackets after "semicircle" means the word "semicircle" comes from the Latin word "semicirculus."
Recognize that a word part with a hyphen at the end of it and followed by a plus (+) sign is the prefix of the word you are analyzing. For example, "semi" is the prefix of "semicircle."
Remove the prefix from the word you are analyzing to find the root of the word. For example, you remove the prefix "semi" from the word "semicircle," leaving "circle." "Circle" is the root of "semicircle."
Look up another word. For example, you look up the word "sempiternity."
Look for the square brackets following the word and the information within the brackets. For example, after "sempiternity" you find "[L. sempiternus (see SEMPITERNAL); + ity]."
Recognize that a word part with a hyphen in front of it and preceded by a plus sign is the suffix of the word you are analyzing. For example, "ity" is the suffix of "sempiternity."
Remove the suffix from the word you are analyzing to find the root of the word. For example, you remove the suffix "ity" from the word "sempiternity," leaving "sempitern." "Sempitern" is the root of "sempiternity."