—adj.
1 continuous (needs constant attention).
2 occurring frequently (receive constant complaints).
3 (often foll. by to) unchanging, faithful, dependable.
—n.
1 anything that does not vary.
2 Math. a component of a relationship between variables that does not change its value.
3 Physics a a number expressing a relation, property, etc., and remaining the same in all circumstances. b such a number that remains the same for a substance in the same conditions.
Derivatives:
constantly adv.
Etymology: ME f. OF f. L constare (as com-, stare stand)
Useful english dictionary. 2012.