An Etymological Dictionary of Astronomy and Astrophysics

1. The amount lost in the process of decreasing.
   

2. Math.: The quantity by which a variable is decreased. A negative → increment.
   

3. Physics: 1) The ratio of the amplitude of an oscillation to that of its succeeding oscillation in an underdamped vibrating system. 2) The intensity ratio of a series of spectral lines of the same nature, such as
   → Balmer decrement.

Etymology (EN): L decrementum, from decre(tus), → decrease + -mentum noun suffix -ment.

Etymology (PE): Kâheh, from kâh- present stem of kâhidan, → decrease + noun suffix -é.