bridging ligand

https://doi.org/10.1351/goldbook.B00741
A ligand attached to two or more, usually metallic, central atoms.
Sources:
Blue Book, p. 338 (http://www.acdlabs.com/iupac/nomenclature/)
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1091 (https://doi.org/10.1351/pac199466051077)
Red Book, 3rd ed., p. 149 (https://doi.org/10.1515/pac-2014-0718)