Dictionary Definition

therefor adv : (in formal usage, especially legal usage) for that or for it; "ordering goods and enclosing payment therefor"; "a refund therefor"

User Contributed Dictionary

Stressed on the second syllable

therefor

For that, or this; for it.
- 1380: Geoffrey Chaucer, Canterbury Tales, "The Squire's Tale" Part 1, - With certeine officers ordeyned therefore [sic.]
- 1892: Benjamin Harrison, Fourth State of the Union Address - During the last fiscal year the Secretary purchased ... 54,355,748 ounces of silver and issued in payment therefor $51,106,608 in notes.

This word is now most commonly used in law.