APPLY', L. applico, of ad and plico, to fold or knit together Gr. to knit, or twist Eng. ply, display, and employ.

1. To lay on to put one thing to another as, to apply the hand to the breast to apply medicaments to a diseased part of the body.
2. To use or employ for a particular purpose, or in a particular case as, to apply a sum of money to the payment of a debt.
3. To put, refer or use, as suitable or relative to something as, to apply the testimony to the case.
4. To fix the mind to engage and employ with attention as, apply thy heart to instruction.
5. To address or direct as, "Sacred vows applied to Pluto."
6. To betake to give the chief part of time and attention as, to apply one's self to the study of botany. This is essentially the fourth sense.
7. To make application to have recourse by request as, to apply one's self to a counsellor for advice. This is generally used intransitively as, to apply to a counsellor.
8. To busy to keep at work to ply. Obs.

Superseded by ply, which see.