bond orbital

https://doi.org/10.1351/goldbook.BT07004
A localized molecular orbital related to a certain $\ce{\upsigma\!\mbox{-}}$, $\ce{\uppi\!\mbox{-}}$, or $\ce{\updelta\!\mbox{-}bond}$.
Source:
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1927 [Terms] [Paper]