pin·o·cy·to·sis  (pĭn'ə-sĭ-tō'sĭs, -sī-, pī'nə-)  n. Introduction of fluids into a cell by invagination of the cell membrane, followed by formation of vesicles within the cells. [Greek pīnein, to drink; see pō(i)- in Indo-European roots + cyt(o)- + -osis.] pin'o·cy·tot'ic (-tŏt'ĭk) adj., pin'o·cy·tot'i·cal·ly adv. |