PHOTORECEPTOR

'Photoreceptor' can refer to:
'In anatomy/cell biology:'

★ Photoreceptor cell: a photosensitive cell, most commonly referring to a specialized type of neuron found in the retina of vertebrate eyes that is capable of phototransduction;

★ Ocellus (invertebrate photoreceptor): a photoreceptor organ ("simple eye") of invertebrates often comprised of a few sensory cells and a single lens;

★ Eyespot apparatus (microbial photoreceptor): the photoreceptor organelle of a unicellular organism that allows for phototaxis.
'In biochemistry:'

★ Photoreceptor protein: a chromoprotein that responds to being exposed to a certain wavelength of light by initiating a signal transduction cascade;

★ Photopigment: an unstable pigment that undergoes a physical or chemical change upon absorbing a particular wavelength of light; also see:

★
★ Photosynthetic pigment: molecules involved in transducing light into chemical energy.
'In technology:'

★ Photodetector or photosensor: a device that detects light by capturing photons