Select the most appropriate one-word substitution for the given group of words.

An extreme fear of height  

Acrophobia

The most appropriate one-word substitution for "an extreme fear of height" is acrophobia.

• Altitudophobia is a fear of high altitudes.
• Heightophobia is a fear of heights, but it is not as specific as acrophobia.
• Pyrophobia is a fear of fire.

The word acrophobia comes from the Greek words "akros," meaning "high," and "phobos," meaning "fear." Acrophobia is a common phobia, and it affects about 5% of the population. People with acrophobia often experience intense anxiety and fear when they are in high places. They may avoid heights altogether, or they may only be able to tolerate them for short periods of time.