Therefore is defined as because something happened.
An example of therefore is saying that you got a cold and then had to stay home from work.
Origin of thereforeMiddle English ther fore: see there and amp; fore as a result of this or that; for this or that reason; consequently; hence: often used as a conjunctive adverb
For that reason or cause; consequently or hence.
Origin of thereforeMiddle English : there, there; see there + for, fore, fore; see for.