Definition of "Constant" :
noun: a quantity that does not vary
noun: a number representing a quantity assumed to have a fixed value in a specified mathematical context
"The velocity of light is a constant."
adjective: steadfast in purpose or devotion or affection
"A man constant in adherence to his ideals."
adjective: uninterrupted in time and indefinitely long continuing
"In constant pain."
adjective: unvarying in nature
"Maintained a constant temperature."