constant

 
Pronunciation: /ˈkɒnst(ə)nt/

adjective

  • occurring continuously over a period of time: the constant background noise of the city
  • remaining the same over a period of time: these discs rotate at a constant speed
  • (of a person) unchangingly faithful and dependable: a constant friend

noun

  • a situation that does not change: the condition of struggle remained a constant
  • Mathematics a quantity or parameter that does not change its value whatever the value of the variables, under a given set of conditions.
  • Physics a number expressing a relation or property which remains the same in all circumstances, or for the same substance under the same conditions.

Origin:

late Middle English (in the sense 'staying resolute or faithful'): from Old French, from Latin constant- 'standing firm', from the verb constare, from con- 'with' + stare 'stand'. The noun senses date from the mid 19th century