therefore

American Heritage® Dictionary of the English Language, Fourth Edition

1. adv. For that reason or cause; consequently or hence.

Century Dictionary and Cyclopedia

1. For that; for this; for it; therefor.
2. In return or recompense for this or for that.
3. For that purpose or cause.
4. For this or for that reason; on that account: referring to something previously stated; consequently; by consequence.
5. Synonyms Therefore, Wherefore, Accordingly, Consequently, Then, So. All these words draw a conclusion or infer a consequence from what immediately precedes; they are all affected by their derivation or original meaning. Therefore, for this or that reason, on that account; wherefore, for which reason, on which account. Therefore is the most formal of the words, and is consequently most used in mathematics, logic, and elaborate argument. The use of wherefore for therefore is not to be commended, as it is considered a Latinism to use a relative pronoun or its derivative for a demonstrative or its derivative in carrying on a thought; the development of this principle is modern, and gives to the demonstrative use of wherefore a tone of quaintness. Accordingly and consequently are more common in essay and narrative writing; then and so in conversation, where brevity is most studied. The last four are more used to indicate practical sequences.

Wiktionary

1. adv. conjunctive For that or this purpose, referring to something previously stated.
2. adv. conjunctive Consequently, by or in consequence of that or this cause; referring to something previously stated.

GNU Webster's 1913

1. For that or this reason, referring to something previously stated; for that.
2. Consequently; by consequence.

WordNet 3.0

1. adv. as a consequence
2. adv. (used to introduce a logical conclusion) from that fact or reason or as a result