tachy-

Tachy- is a combining form used like a prefix meaning “swift.” It is often used in scientific and medical terms.

Tachy- comes from the Greek �ٲ�����ý��, meaning “swift.”

������ are variants of tachy-?

A variant of tachy- is tacheo-, as in tacheometer. Closely related to tachy- is the combining form tacho-, which you can learn more about in our Words That Use tacho- article.

An example of a medical term that features the combining form tachy- is tachypnea, meaning “excessively rapid respiration.”

The word tachypnea is made of two combining forms. The first is tachy- which we know means “swift.” The second is -pnea which means “breath, respiration,” as we explain in our Words That Use -pnea article. Tachypnea translates literally to “swift breathing.”

Some theoretical physicists have speculated on the existence of the tachyon, a theoretical subatomic particle that travels faster than the speed of light—which would violate the laws of physics as we know them!

������ are some words that use the combining form tachy-?

• tachycardia
• tachygraphy
• tachylyte
• tachymeter
• tachyon
• tachyrhythmia
• tachytelic

������ are some other forms that tachy- may be commonly confused with?

• pachy-
• techno-

Despite being a homonym, the word tacky does not share the same root as tachy-. Find out what makes tacky unique at our entry for the word.

Tachy- means “swift” and -cardia refers to the heart. Can you figure out, then, what tachycardia is?