<p><strong>Noun</strong></p><ul><li>Biology. an unattached cell, especially of a kind that floats freely, as a blood or lymph cell.</li><li>Anatomy. a small mass or body forming a more or less distinct part, as the sensory receptors at nerve terminals.</li><li>Physical Chemistry. a minute or elementary particle of matter, as an electron, proton, or atom.</li><li>any minute particle.</li></ul>