"The application of immunological methods (such as immunofluorescence, immunoperoxidase, etc.) in histochemistry; the study of the constituents of tissues and cells using such methods. Also: the immunohistochemical characteristics of a cell or tissue type, cellular constituent, etc", 1960s; earliest use found in Journal of Cell Biology. From immuno- + histochemistry, after immunohistochemical.[immunohistochemistry etymology, immunohistochemistry origin, 英语词源]