前缀actino-在元音前变成actin-,意思是“A ray or beam 光线，束”。前缀actino-来源极其复杂和曲折，它来源于希腊语aktis,意思是“ray, radiance 光线，射线等多个意思”，aktis可能与梵文aktuh (意思是“light,ray”)同族。

这个前缀也可以作为词根讲，作为词根时，与这个词根-actino-（意思是“光，光线，呈放射状的”）异形同义词根有：-rad-,-rad-,-radio-,radi-,这几个词根来源于radix,radius/radiare 光,辐射。

词源：

before vowels actin-, word-forming element meaning "pertaining to rays," from Greek aktis (genitive aktinos) "ray, radiance;" perhaps cognate with Sanskrit aktuh "light, ray," Gothic uhtwo "dawn, daybreak," Lithuanian anksti "early."

这里通过对这个前缀的应用，举了一些由这个前缀构成的单词例子:

Some examples refer to rays of light. Radiation that is able to cause chemical reactions, as light does on photographic film, is said to be actinic; an actinometer is an instrument for measuring the intensity of radiation. Actinium is a rare radioactive element (atomic number 89), so named because it glows in the dark; hence actinide, a member of the series of radioactive elements, including uranium and plutonium, of which actinium is the first.

Other examples refer to structures that radiate from a centre. Something actinomorphic, such as a starfish or the flower of a daisy, has radial symmetry. An actinomycete (Greek mukēs, mukēt-, fungus) is a bacterium with a filamentous form, which was formerly considered to be a fungus, the ray-fungus; these can cause disease in humans and animals; actinomycin is a member of a group of antibiotics extracted from soil bacteria of this genus.