1. (Science: biology) cells found in the epithelial lining of the labyrinth of the inner ear. The hairs are stereovilli up to 25 m long that restrict the plane in which deformation of the apical membrane of the cell can be brought about by movement of fluid or by sound. Movement of the single stereocilium transduces mechanical movements into electrical receptor potentials.
2. (Science: plant biology) many plant surfaces are covered with fine hairs (tradescantia stamens are a common source), the hairs are made up of thin walled cells that are convenient for studying cytoplasmic streaming and for observing mitosis.