An amplification is an act of amplifying, expanding or making larger, or the act of increasing some quantity such as voltage, power or current.

A: Vacuum tubes are current amplifiers transistors are voltage amplifier. The voltage drop across the collector resistor causes amplification since very little current in the base will change a large current in the collector.

IC/IB where IC is Collector Current and IB is Base Current

a transistor ampify the current

i.e. you the output current proportional to the input one.

in CE amplifier , this ratio is more than one Ic/Ib = current amplification factor

this extra ampitude comes from the biasing batteries used.

A direct current dynamo with a major 'amplification'. Driven by a turbine.