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.
PAC, 1997, 69, 1137 (Glossary of terms used in computational drug design (IUPAC Recommendations 1997)) on page 1149