OH

n. ouch!; ah!; wow!; really! (expression of surprise, pain, pleasure, confusion)

interj. wow! (cry of surprise, interest, etc.)

Oh is an interjection with many uses, often said by people realizing something.
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In chemistry, an alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. The general formula for a simple acyclic alcohol is CnH2n+1OH. In layman's terms, the word alcohol (, "al-kuḥl") usually refers to ethanol, also known as grain alcohol or (older) spirits of wine, or to any alcoholic beverage. Ethanol is a colorless, volatile liquid with a mild odor which can be obtained by the fermentation of sugars. (Industrially, it is more commonly obtained by ethylene hydration — the reaction of  ethylene with water in the presence of phosphoric acid.) Ethanol is the most widely used depressant in the world, and has been for thousands of years. This sense underlies the term alcoholism (addiction to alcohol).
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In chemistry, hydroxide is the most common name for the diatomic anion OH−, consisting of oxygen and hydrogen atoms, usually derived from the dissociation of a base. It is one of the simplest diatomic ions known.Inorganic compounds that contain the hydroxyl group are referred to as hydroxides. Common hydroxides include:Sodium hydroxide (NaOH)Potassium hydroxide (KOH)Calcium hydroxide (Ca(OH)2)Ammonium hydroxide (NH4OH)
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Noun
1. a midwestern state in north central United States in the Great Lakes region
(synonym) Ohio, Buckeye State
(hypernym) American state
(part-holonym) Midwest, Middle West
(part-meronym) Akron

interj. oh! (expression of understanding); oh! (cry of surprise); ouch!, ah!; really! (expression of surprise, pain, pleasure, confusion)

interj. oh, wow! (cry of surprise, interest, etc.)