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Heli- is a combining form used like a prefix that has two distinct senses.

The first of these senses is “sun,” and this form of heli- is occasionally used in a variety of scientific and technical terms. Heli- comes from Greek ��������Dz�, meaning “sun.” The Latin cognate, ��ō��, is the source of several words related to the sun, such as solar and solstice.

The second of these senses is “helicopter,” and this form of heli- is occasionally used in a variety of technical terms. Heli- comes from the word helicopter in a bit of a roundabout way. The word helicopter comes from French ���������DZ�è�ٰ��� and is a combination of two forms: helico-, meaning “spiral,” and -pter, meaning “one with wings.” However, helicopter is abbreviated using only the first syllable, heli-. Find out more about the word helicopter at our entry for the word.

What are variants of heli- with the sense “sun”?

Heli- is a variant of helio-, which loses its -o- when combined with words or word elements beginning with vowels. Want to know more? Read our 51�Թ�s That Use article for helio-.

An example of a scientific term that features the form heli- to mean “sun” is helianthus, “any composite plant of the genus Helianthus, comprising the sunflowers.” Helianthus in English comes from Latin Helianthus, which uses the Latin equivalent form of heli-.

The heli- part of the word means “sun,” while -anthus means “having flowers,” from Greek á�Գٳ�Dz�. Helianthus literally translates to “having sun flowers.”

What are some words that use the combining form heli-?

• heliacal (using the equivalent form of heli- in Greek)
• heliacal rising
• helianthemum (using the equivalent form of heli- in Latin)
• heliencephalitis

What are some other forms that heli- may be commonly confused with?

• helic-
• helico-

Break it down!

Encephalitis is a medical condition of inflammation of the brain. Given the meaning of heli-, what is the cause of heliencephalitis?

One word that features the combining form heli- to mean “helicopter” is heliborne, “transported by helicopter.”

While heli- here stands for “helicopter,” the -borne portion of the word comes from an abbreviation of airborne, meaning “carried by the air.” Heliborne literally means “carried by a helicopter.”

What are some words that use the combining form heli-?

• helideck
• helidock
• helilift
• heliport
• heliskiiing
• helitaxi

What are some other forms that heli- may be commonly confused with?

• helic-
• helico-

Break it down!

Some folks don’t travel like the rest of us; they take helitaxis to get from place to place, especially in dense cities. With the meaning of the combining for heli- in mind, what is a helitaxi?