What is the definition of the word endeavor?

Answer 1

Dictionary.com defines endeavor as:

-verb (used without object) 1. to exert oneself to do or effect something; make an effort; strive: We must constantly endeavor if we are to succeed.
-verb (used with object) 2. to attempt; try: He endeavors to keep things neat in his apartment. 3. Archaic. to attempt to achieve or gain.
-noun 4. a strenuous effort; attempt.

It goes on to point out that the British English spelling is endeavour.

It explains its origin as being 1350-1400 Middle English; endeveren, from the phrase putten in devoir; to make an effort.