Source : Webster's Revised Unabridged Dictionary (1913)

Ampere minute \Amp[`e]re minute\ and Ampere second \Amp[`e]re
second\ are sometimes similarly used. Ampere turn \Amp[`e]re
turn\ (Elec.)
   A unit equal to the product of one complete convolution (of a
   coiled conductor) into one amp[`e]re of current; thus, a
   conductor having five convolutions and carrying a current of
   half an amp[`e]re is said to have 21/2 amp[`e]re turns. The
   magnetizing effect of a coil is proportional to the number of
   its amp[`e]re turns.