Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.
tight junction[¦tīt ′jəŋk·shən]
(cell and molecular biology)
An intercellular junction composed of a series of fusions of the junctional membrane, forming a continuous seal; serves as a selective barrier to small molecules and as a total barrier to large molecules. Also known as impermeable junction; occluding junction; zonula occludens.