›a chemical that combines two or more elements: Salt is a compound of sodium and chlorine.Many fertilizers contain nitrogen compounds.Types of chemicalSpecific chemicals, chemical compounds and gasesSubstances and structures in the body›formalsomething consisting of two or more different parts: Then there was his manner, a curious compound of humour and severity.ComplexityDifficult to understand›in grammar, a word that combines two or more different words. Often, the meaning of the compound cannot be discovered by knowing the meaning of the different words that form it. Compounds may be written either as one word or as separate words: 'Bodyguard' and 'floppy disk' are two examples of compounds.Morphology and parts of words