hydrogen bond

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially a nitrogen, oxygen, or fluorine atom, usually of another molecule.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry 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.
• verb chemistry To bond to another species by means of hydrogen bonds. E.g. Water hydrogen bonds with itself.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun 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