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American Heritage Dictionary - Cite This Source - Share This

then       (thěn)  Pronunciation Key  adv.   At that time: I was still in school then. Come at noon; I'll be ready then. Next in time, space, or order; immediately afterward: watched the late movie and then went to bed. In addition; moreover; besides: It costs $20, and then there's the sales tax to pay. Used after but to qualify or balance a preceding statement: The star was nervous, but then who isn't on the first night of a new play. In that case; accordingly: If traffic is heavy, then allow extra time. As a consequence; therefore: The case, then, is closed. n.   That time or moment: The bus leaves at four; until then let's walk. adj.   Being so at that time: the then chairman of the board. [Middle English, from Old English thenne; see to- in Indo-European roots.]

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then 

WordNet - Cite This Source - Share This

then
adjective
1.	at a specific prior time; "the then president"
adverb
1.	subsequently or soon afterward (often used as sentence connectors); "then he left"; "go left first, then right"; "first came lightning, then thunder"; "we watched the late movie and then went to bed"; "and so home and to bed"
2.	in that case or as a consequence; "if he didn't take it, then who did?"; "keep it then if you want to"; "the case, then, is closed"; "you've made up your mind then?"; "then you'll be rich"
3.	at that time; "I was young then"; "prices were lower back then"; "science as it was then taught"
noun
1.	that time; that moment; "we will arrive before then"; "we were friends from then on"

American Heritage Dictionary of Idioms - Cite This Source - Share This

then

In addition to the idioms beginning with then, also see and then some; every now and then.

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Then

Then\ ([th][e^]n), adv. [Originally the same word as than. See Than.]

1. At that time (referring to a time specified, either past or future).

And the Canaanite was then in the land. --Gen. xii. 6.

Now I know in part; but then shall I know even as also I am known. --1 Cor. xiii. 12.

2. Soon afterward, or immediately; next; afterward.

First be reconciled to thy brother, and then come and offer thy gift. --Matt. v. 24.

3. At another time; later; again.

One while the master is not aware of what is done, and then in other cases it may fall out to be own act. --L'Estrange.

By then. (a) By that time. (b) By the time that. [Obs.]

But that opinion, I trust, by then this following argument hath been well read, will be left for one of the mysteries of an indulgent Antichrist. --Milton.

Now and then. See under Now, adv.

Till then, until that time; until the time mentioned. --Milton.

Note: Then is often used elliptically, like an adjective, for then existing; as, the then administration.

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Then

Then\, conj. 1. Than. [Obs.] --Spenser.

2. In that case; in consequence; as a consequence; therefore; for this reason.

If all this be so, then man has a natural freedom. --Locke.

Now, then, be all thy weighty cares away. --Dryden.

Syn: Therefore.

Usage: Then, Therefore. Both these words are used in reasoning; but therefore takes the lead, while then is rather subordinate or incidental. Therefore states reasons and draws inferences in form; then, to a great extent, takes the point as proved, and passes on to the general conclusion. "Therefore being justified by faith, we have peace with God." --Rom. v. 1. "So then faith cometh by hearing, and hearing by the word of God." --Rom. x. 17.