To have at one's fingers' ends

Finger Fin"ger (f[i^][ng]"g[~e]r), n. [AS. finger; akin to D. vinger, OS. & OHG. fingar, G. finger, Icel. fingr, Sw. & Dan. finger, Goth. figgrs; of unknown origin; perh. akin to E. fang.] 1. One of the five terminating members of the hand; a digit; esp., one of the four extremities of the hand, other than the thumb. [1913 Webster]

2. Anything that does the work of a finger; as, the pointer of a clock, watch, or other registering machine; especially (Mech.) a small projecting rod, wire, or piece, which is brought into contact with an object to effect, direct, or restrain a motion. [1913 Webster]

3. The breadth of a finger, or the fourth part of the hand; a measure of nearly an inch; also, the length of finger, a measure in domestic use in the United States, of about four and a half inches or one eighth of a yard. [1913 Webster]

A piece of steel three fingers thick. --Bp. Wilkins. [1913 Webster]

4. Skill in the use of the fingers, as in playing upon a musical instrument. [R.] [1913 Webster]

She has a good finger. --Busby. [1913 Webster]

{Ear finger}, the little finger.

{Finger alphabet}. See {Dactylology}.

{Finger bar}, the horizontal bar, carrying slotted spikes, or fingers, through which the vibratory knives of mowing and reaping machines play.

{Finger board} (Mus.), the part of a stringed instrument against which the fingers press the strings to vary the tone; the keyboard of a piano, organ, etc.; manual.

{Finger bowl} {Finger glass}, a bowl or glass to hold water for rinsing the fingers at table.

{Finger flower} (Bot.), the foxglove.

{Finger grass} (Bot.), a kind of grass ({Panicum sanguinale}) with slender radiating spikes; common crab grass. See {Crab grass}, under {Crab}.

{Finger nut}, a fly nut or thumb nut.

{Finger plate}, a strip of metal, glass, etc., to protect a painted or polished door from finger marks.

{Finger post}, a guide post bearing an index finger.

{Finger reading}, reading printed in relief so as to be sensible to the touch; -- so made for the blind.

{Finger shell} (Zo["o]l.), a marine shell ({Pholas dactylus}) resembling a finger in form.

{Finger sponge} (Zo["o]l.), a sponge having finger-shaped lobes, or branches.

{Finger stall}, a cover or shield for a finger.

{Finger steel}, a steel instrument for whetting a currier's knife. [1913 Webster]

{To burn one's fingers}. See under {Burn}.

{To have a finger in}, to be concerned in. [Colloq.]

{To have at one's fingers' ends}, to be thoroughly familiar with. [Colloq.] [1913 Webster]