Meaning of hydronium ion

hy•dro'ni•um i"on

Pronunciation: (hī-drō'nē-um), [key]
  1. the hydrogen ion bonded to a molecule of water, HO⫀, the form in which hydrogen ions are found in aqueous solution. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.