- a binary compound formed by hydrogen and another, usually more electropositive, element or group, as sodium hydride, NaH, or methyl hydride, CH4.
- any compound of hydrogen with another element, including ionic compounds such as sodium hydride (NaH), covalent compounds such as borane (B 2 H 6), and the transition metal hydrides formed when certain metals, such as palladium, absorb hydrogen
