The word better can be an adjective, adverb and verb.
As an adjective, better is the comparative form of the adjective good.
- She is a better dancer than me. (Informal)
- She is a better dancer than I am. (More formal)
Better can mean greater, larger, bigger and longer.
- The better part of the day was spent in working.
Better can also mean stronger, fitter or healthier.
- Grandpa is better today. (= He is healthier today.)
Better can also be an adverb. As an adverb, better is the comparative form of well.
- Learn to play a little better before joining the team.
- You sing better than your sister.
Better can mean more or longer.
- It takes better than an hour to get to the airport. (= It takes more than an hour …)
As a verb, better means improve, advance or upgrade.
- He tried to better himself by obtaining more degrees.
Better can also mean surpass or exceed.
- The pole vaulter bettered the world record by six inches.