Put into practical use.

Of a branch of science, serving another branch of science or engineering.

To lay or place; to put (one thing to another)

"to apply cream to a rash"

To put to use; to use or employ for a particular purpose, or in a particular case

"to apply funds to the repayment of a debt"

To make use of, declare, or pronounce, as suitable, fitting, or relative

"We need to apply the skills we've learned to solve this problem"

To put closely; to join; to engage and employ diligently, or with attention

To to address; to refer; generally used reflexively.

To submit oneself as a candidate (with the adposition "to" designating the recipient of the submission, and the adposition "for" designating the position).

"I recently applied to the tavern for a job as a bartender."

To pertain or be relevant to a specified individual or group.

"That rule only applies to foreigners."

To busy; to keep at work; to ply.

To visit.