(biochemistry, uncountable) A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament). / (biochemistry, countable) One of the six isoforms of actin.

(zoology) Pertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish. / (zoology) Pertaining to the axis of rotational symmetry in radiate animals.

Alternative form of actino-

In an actinic manner.

Of or relating to actinism.

Pronunciation spelling of acting.

In an actinal manner.

(inorganic chemistry) Any oxyanion of actinium, or salt containing such an oxyanion

plural of actin

(chemistry, physics) That property of electromagnetic radiation that leads to the production of photochemical effects