Invariant
WordNet
adjective
(1) Persistent in occurrence and unvarying in nature
"Maintained a constant temperature"
"Principles of unvarying validity"
(2) Unaffected by a designated operation or transformation
noun
(3) A feature (quantity or property or function) that remains unchanged when a particular transformation is applied to it
WiktionaryText
Adjective
- not varying; constant
- Unaffected by a specified operation (especially by a transformation)
Noun
- An invariant quantity, function etc.