Which meaning does the prefix geo- denote?

• A. In front of
• B. Earth
• C. Above, over
• D. Not

Answer: (B)

Geo- denotes Earth. This prefix appears in many science terms that relate to our planet—geography describes the Earth’s surfaces, geology is the study of the Earth’s materials and structure, and geothermal refers to heat that comes from the Earth. The root comes from a Greek word for Earth, so the common thread is Earth-related meaning. Prefixes meaning “in front of” or “before” come from different roots (like ante- or pro-), prefixes meaning “above” come from words like super- or epi-, and prefixes meaning “not” come from negation roots like non- or un-. Since geo- clearly ties to the Earth, it is the best fit for the meaning being asked.