definition atp
Definition of ATP. : a phosphorylated nucleotide C10H16N5O13P3 composed of adenosine and three phosphate groups that supplies energy for many biochemical cellular processes by undergoing enzymatic hydrolysis especially to ADP âcalled also adenosine triphosphate.See ATP defined for kids.ADVERTISEMENT. a phosphorylated nucleotide C10H16N5O13P3 composed of adenosine and three phosphate groups that supplies energy for many biochemical cellular processes by undergoing enzymatic hydrolysis especially to ADP âcalled also adenosine triphosphate. See ATP defined for kids.