The Collaborative International Dictionary of English v.0.48:
Eye-spot \Eye"-spot`\, n. (Zo["o]l.) (a) A simple visual organ found in many invertebrates, consisting of pigment cells covering a sensory nerve termination. (b) An eyelike spot of color. [1913 Webster]WordNet (r) 3.0 (2006):
eyespot n 1: an eyelike marking (as on the wings of some butterflies); usually a spot of color inside a ring of another color [syn: eyespot, ocellus]