Emily Dickinson Lexicon

AP-PLY', v.t. [L. applico, of ad and plico, to fold or knit together; Fr. appliquer; Sp, aplicar; It. applicare; W. plegy, to bend or fold; Arm. plega, to fold or plait; pleca, a fold; Gr. πλεκω, to knit, or twist; Sax. plegan, plegian, pleggan, to play, to bend to or apply, incumbere; Dan. fliig, a fold; D. plooi, a fold; ploojen, to plait; Eng. ply, display, and employ. The word plegy, plico is formed from the root of lay, Sax. lecgan. The sense then is to lay to; and it is worthy of remark, that we use lay to in the precise sense of ply and apply. It is certain from the Welsh that the first consonant is a prefix.]

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.” – Proverbs.
5. To address or direct; as, “Sacred vows applied to Pluto.” Pope.
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 counselor for advice. This is generally used intransitively; as, to apply to a counselor.
8. To busy; to keep at work; to ply. [Obs.] – Sidney. Spenser. [Superseded by ply, which see.]