Ligand

Noun

1. A molecule or moiety (ion, functional group, or radical) that binds to another chemical entity to form a larger complex; as, especially: (coordination chemistry) Such an entity that binds to a central metal atom to form a coordination complex. Such an entity that forms a complex with a biomolecule to serve a biological purpose.
2. (coordination chemistry) Such an entity that binds to a central metal atom to form a coordination complex.
3. Such an entity that forms a complex with a biomolecule to serve a biological purpose.
4. A letter that orthography requires or allows to be ligated with one or more other letters to form a ligature, such as a in æ or o in œ.