Back \Back\, adv. [Shortened from aback.]

1. In, to, or toward, the rear; as, to stand back; to step back.

2. To the place from which one came; to the place or person from which something is taken or derived; as, to go back for something left behind; to go back to one's native place; to put a book back after reading it.

3. To a former state, condition, or station; as, to go back to private life; to go back to barbarism.

4. (Of time) In times past; ago. ``Sixty or seventy years back.'' --Gladstone.

5. Away from contact; by reverse movement.

The angel of the Lord . . . came, and rolled back the stone from the door. --Matt. xxvii. 2.

6. In concealment or reserve; in one's own possession; as, to keep back the truth; to keep back part of the money due to another.

7. In a state of restraint or hindrance.

The Lord hath kept thee back from honor. --Numb. xxiv. 11.

8. In return, repayment, or requital.

What have I to give you back! --Shak.

9. In withdrawal from a statement, promise, or undertaking; as, he took back0 the offensive words.

10. In arrear; as, to be back in one's rent. [Colloq.]

Back and forth, backwards and forwards; to and fro.

To go back on, to turn back from; to abandon; to betray; as, to go back on a friend; to go back on one's professions. [Colloq.]

Source: Webster's Revised Unabridged Dictionary (1913)
 

Forth \Forth\, v.[AS. for[eth], fr. for akin to D. voort, G. fort [root]78. See Fore, For, and cf. Afford, Further, adv.]

1. Forward; onward in time, place, or order; in advance from a given point; on to end; as, from that day forth; one, two, three, and so forth.

Lucas was Paul's companion, at the leastway from the sixteenth of the Acts forth. --Tyndale.

From this time forth, I never will speak word. --Shak.

I repeated the Ave Maria; the inquisitor bad me say forth; I said I was taught no more. --Strype.

2. Out, as from a state of concealment, retirement, confinement, nondevelopment, or the like; out into notice or view; as, the plants in spring put forth leaves.

When winter past, and summer scarce begun, Invites them forth to labor in the sun. --Dryden.

3. Beyond a (certain) boundary; away; abroad; out.

I have no mind of feasting forth to-night. --Shak.

4. Throughly; from beginning to end. [Obs.]

--Shak.

And so forth, Back and forth, From forth. See under And, Back, and From.

Forth of, Forth from, out of. [Obs.]

--Shak.

To bring forth. See under Bring.

Source: Webster's Revised Unabridged Dictionary (1913)