1540s, "enlargement," from Latin amplificationem (nominative amplificatio) "a widening, extending," noun of action from past participle stem of amplificare (see amplify). Electronics sense is from 1915.
An increase in the magnitude or strength of an electric current, a force, or another physical quantity, such as a radio signal.
An increase in the number of copies of a gene in a cell, resulting in an elevation in the level of the RNA or protein encoded for by the gene and a corresponding amplification of the phenotype that the gene confers on the cell. Drug resistance in cancer cells is linked to amplification of the gene that prevents absorption of the chemotherapeutic agent by the cell.
A process in a cell by which a particular gene is replicated so that more copies are available to produce a protein for the cell's use. For example, the genes that code for proteins involved in ribosomes are amplified early in the process of cell development so that there are sufficient numbers of them to assemble the cell.