Aldehyde

 An aldehyde is an organic compound with the functional group R–CHO. The functional group is a terminal carbon atom double bonded to oxygen, forming a carbonyl group, bonded to hydrogen and an R group. The group –CHO is known as an aldehyde group and is only found at the end of the carbon chain; a carbonyl group found within the carbon chain is part of the functional group of a ketone.

Aldehydes are common to organic chemistry and are an important feature, along with ketones, of carbohydrates.