Our online medical glossary of medical terms and definitions includes definitions for terms related to treatment, and general medicine
CYTOKINE
Little proteins or biological factors (in the range of 5-20 kD) that are released by cells and have specific effects on cell-cell interaction, communication and behaviour of another cells.
Not indeed various from hormones, but the term tends to be used as a convenient genericshorthand for interleukins, lymphokines and different related signalling molecules such as TNF and interferons.
Generally growth factors would not be classified as cytokines, though TGF is an exception. Rather an imprecise term. Chemokines are a subset of cytokines.