cAMP is the abbreviation for cyclic adenosine mono phosphate, a cyclic nucleotide of adenosine that acts at the cellular level to regulate various metabolic processes and mediate the effects of many hormones; so it is also known as second messenger where hormones are the first messengers.

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Adenosine is a nucleoside (C₁₀H₁₃N₅O₄), composed of adenine linked to ribose, that is a structural component of nucleic acids and the major molecular component of ADP, AMP, and ATP.

Adenine is a purine base ( C₅H₅N₅), that is the constituent involved in base pairing with thymine in DNA and with uracil in RNA.

Ribose is a pentose sugar ( C₅H₁₀O₅), occurring as a component of riboflavin, nucleotides, and nucleic acids.

Pentose is any of a class of monosaccharides having five carbon atoms per molecule and including ribose and several other sugars.

Monosaccharide is any of several carbohydrates, such as tetroses, pentoses, and hexoses, that cannot be broken down to simpler sugars by hydrolysis. Also called simple sugar.

carbohydrate is any of a group of organic compounds that includes sugars, starches, celluloses, and gums and serves as a major energy source in the diet of animals. These compounds are produced by photosynthetic plants and contain only carbon, hydrogen, and oxygen, usually in the ratio 1:2:1.

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Source: American Heritage Dictionary