What does "apply" mean?

Apply: To put to use; to use or employ for a particular purpose, or in a particular case; to appropriate; to devote; as, to apply money to the payment of a debt.

Additional senses

  1. 2.To make use of, declare, or pronounce, as suitable, fitting, or relative; as, to apply the testimony to the case; to apply an epithet to a person. Yet God at last To Satan, first in sin, his doom applied. Milton.
  2. 3.To fix closely; to engage and employ diligently, or with attention; to attach; to incline. Apply thine heart unto instruction. Prov. xxiii.
  3. 4.5. To direct or address. [R.] Sacred vows . . . applied to grisly Pluto. Pope.
  4. 5.To betake; to address; to refer; -- used reflexively. I applied myself to him for help. Johnson.
  5. 6.To busy; to keep at work; to ply. [Obs.] She was skillful in applying his "humors." Sir P. Sidney.
  6. 7.To visit. [Obs.] And he applied each place so fast. Chapman. Applied chemistry. See under Chemistry. -- Applied mathematics. See under Mathematics.
  7. 8.To suit; to agree; to have some connection, agreement, or analogy; as, this argument applies well to the case.
  8. 9.To make request; to have recourse with a view to gain something; to make application. (to); to solicit; as, to apply to a friend for information.
  9. 10.To ply; to move. [R.] I heard the sound of an oar applying swiftly through the water. T. Moore.
  10. 11.To apply or address one's self; to give application; to attend closely (to).

Sources