constant

(noun) a quantity that does not vary. Synonyms: constant quantity, invariable.

(noun) a number representing a quantity assumed to have a fixed value in a specified mathematical context. Example: "The velocity of light is a constant."

(adj) unvarying in nature. Synonyms: changeless, invariant, unvarying. Examples: "Maintained a constant temperature." "Principles of unvarying validity."

(adj) steadfast in purpose or devotion or affection. Synonyms: constant (vs. inconstant). Examples: "A man constant in adherence to his ideals." "A constant lover." "Constant as the northern star."

(adj) uninterrupted in time and indefinitely long continuing. Synonyms: ceaseless, incessant, never-ending, perpetual, unceasing, unremitting. Examples: "The ceaseless thunder of surf." "In constant pain." "Night and day we live with the incessant noise of the city." "The never-ending search for happiness." "The perpetual struggle to maintain standards in a democracy." "Man's unceasing warfare with drought and isolation." "Unremitting demands of hunger."