the eye unaided by any optical instrument that alters the power of vision or alters the apparent size or distance of objects; "it is not safe to look directly at the sun with the naked eye"
animal reproductive body consisting of an ovum or embryo together with nutritive and protective envelopes; especially the thin-shelled reproductive body laid by e.g. female birds
oval reproductive body of a fowl (especially a hen) used as food
a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tubelike structure extending from the base of the brain through the vertebral canal to the upper lumbar region
the junction between two neurons (axon-to-dendrite) or between a neuron and a muscle; "nerve impulses cross a synapse through the action of neurotransmitters"
(biology) the field of science concerned with processes of communication and control (especially the comparison of these processes in biological and artificial systems)
colorless watery fluid of blood and lymph containing no cells and in which erythrocytes and leukocytes and platelets are suspended
(physical chemistry) a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors; a gas becomes a plasma when it is heated until the atoms lose all their electrons, leaving a highly electrified collection of nuclei and free electrons; "particles in space exist in the form of a plasma"
a green slightly translucent variety of chalcedony used as a gemstone