noun
a nucleotide, CHNOP, present in, and vital to the energy processes of, all living cells: during biological oxidations energy is stored in the ATP molecule as ADP is converted to ATP, which later converts back to ADP, releasing the energy needed for muscular contractions, photosynthesis, bioluminescence, biosynthesis, etc.
Origin:
a(denosine) d(i)p(hosphate)