bet·ter 1 
(bĕtər)
(bĕtər)adj. Comparative of good.
1. Greater in excellence or higher in quality: Which of the twins is the better skater?
2. More useful, suitable, or desirable: found a better way to go; a suit with a better fit than that one.
3. More highly skilled or adept: I am better at math than English.
4. Greater or larger: argued for the better part of an hour.
5. More advantageous or favorable; improved: a better chance of success.
6. Healthier, more fit, or in less discomfort than before: The patient is better today.
adv. Comparative of well2.
1. In a more excellent way: He sings better than his father.
2.
a. To a greater extent or degree: better suited to the job; likes it better without sauce.
b. To greater advantage; preferably: a deed better left undone. See Usage Notes at best, have, rather.
3. More: It took me better than a year to recover.
n.
1. One that is greater in excellence or higher in quality.
2. often betters A superior, as in standing, competence, or intelligence: to learn from one's betters.
v. bet·tered, bet·ter·ing, bet·ters
v. tr.
1. To make better; improve: trying to better conditions in the prison; bettered myself by changing jobs.
2. To surpass or exceed: practiced so he could better his rival.
v. intr.
Idioms: To become better: Conditions bettered with time.
better off
In a better or more prosperous condition: would be better off taking the train instead of driving; felt better off after the rise in stock prices.
for the better
Resulting in or aiming at an improvement: Her condition took a turn for the better.
get (or have)the better of
To outdo or outwit; defeat.
think better of
To change one's mind about (a course of action) after reconsideration: I almost bought an expensive watch, but then I thought better of it.
[Middle English, from Old English betera; see bhad- in the Appendix of Indo-European roots.]