a coenzyme present in most living cells and derived from the B vitamin nicotinic acid; serves as a reductant in various metabolic processes
"The enzyme requires nad to function as an electron carrier during cellular respiration."
noun animate dependent
"The enzyme requires NAD to function as a coenzyme in redox reactions."
testicle
Initialism of nicotinamide adenine dinucleotide.
"She was surprised to see that there were no more sodas left in the fridge, so she went out to buy some nad for her guests."
Initialism of nothing abnormal discovered (or detected).
"The ultrasound report came back nad, confirming that there were no abnormalities in the fetus's development."
The word nad is a clipped form of the medical term gonad. It entered English as an informal abbreviation referring to reproductive organs.