An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

General:The greatness, size, or extent of something.
In any periodically varying function, the maximum absolute value of the quantity.
The magnitude range of a variable star.

L. amplitudo "wide extent, width," from amplus "large".

Dâmané "the foot or skirt of a mountain," from dâman "skirt."