1.NounA unit of electrical current, the standard base unit in the International System of Units; colloquially amp. Abbreviation: amp, Symbol: A"Definition: The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 x 10 when expressed in the unit C, which is equal to A s, where the second is defined in terms of ΔνCs. (The International Bureau of Weights and Measures)"