What is Constant ?
Constant is (adj) 1. not changing or stopping The constant noise of music from the bar next door drives me mad. 2. loyal to someone and always with them His dog was his constant companion. 3. with a value which does not change The calculations are in constant dollars.(noun) a number or thing which does not change The speed of light is a constant. Death and taxes are the only constants in life.
source: Easier English, Student Dictionary Upper Intermediate Level