receptor

in drug design
A receptor is a protein or a protein complex in or on a cell that specifically recognizes and binds to a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc). In a broader sense, the term receptor is often used as a synonym for any specific (as opposed to non-specific such as binding to plasma proteins) drugbinding site, also including nucleic acids such as DNA.
Source:
PAC, 1997, 69, 1137 (Glossary of terms used in computational drug design (IUPAC Recommendations 1997)) on page 1149