•
An, in mathematics, a
root system and its Dynkin diagram •
An, in mathematics, conventional notation for the
alternating group •
an, a generic label for a term of a
sequence •
AN thread, Army and Navy thread - for bolts and tube fittings in 16th inch increments •
Acanthosis nigricans, a skin condition •
Acrylonitrile, an organic compound and monomer used in the manufacture of certain plastics •
Actinide (An), informal symbol for a series of chemical elements •
Ammonium nitrate (AN), a chemical compound •
Anode, in electronic schematics •
Anorexia nervosa, an eating disorder •
Application note (in engineering), most often seen as A.N. •
Attonewton (aN), an SI unit of force •
Anorthite, a feldspar mineral •
Adobe Animate, an Adobe animation software == Military ==