A chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic bond WordNet 3.0 & Open English WordNet

In chemistry, a hydrogen bond is primarily an electrostatic force of attraction between a hydrogen atom which is covalently bonded to a more electronegative "donor" atom or group, and another electronegative atom bearing a lone pair of electrons—the hydrogen bond acceptor. Wikipedia

Form of association between an electronegative atom and a hydrogen atom attached to a second, relatively electronegative atom Wikidata

A weak bond in which a hydrogen atom in one molecule is attracted to an electronegative atom (usually nitrogen or oxygen) in the same or different molecule. Wiktionary

Weak bond. Wiktionary (translation)