so much the better Definition

better¹
adj

1. More excellent, suitable or desirable, etc.

Thesaurus: superior, greater, finer, preferred, stronger, surpassing, worthier.
2. More successful, skilful, etc in doing it.

Form: better at something (usually)
3. Partly or fully improved in health or recovered from illness.

Thesaurus: convalescent, recovering, improving, mending, progressing, restored, cured; Antonym: worse, failing.
Form: be better (especially)
Form: feel better
Form: get better
4. Greater.

Example: the better part of a day

adverb

1. More excellently, successfully or fully, etc.

Example: You can see better from here
2. In or to a greater degree.

Example: knows the area better than I do

noun

1. A person superior in quality or status, etc.

Example: Respect your elders and betters
Form: betters (especially)
2. The thing or person that is the more excellent or suitable, etc of two comparable things or people.

Example: This is the better of my two attempts
Form: the better

verb bettered, bettering

1. To beat or improve on something.

Example: can't better his original score
Thesaurus: excel, surpass, transcend, outdo, outstrip.
2. To make something more suitable, desirable or excellent, etc.

Example: set out to better the conditions for the workers
Thesaurus: improve, revamp, refine, further, ameliorate; Antonym: deteriorate, worsen.

Idiom: all the better for something

Very much better as a result of it.

Idiom: better off

More affluent or fortunate; wealthier or in happier circumstances.

Idiom: better oneself

To improve one's position or social standing.

Idiom: for better or for worse

No matter what happens.
Thesaurus: regardless, in any event, no matter what happens, anyhow.

Idiom: get the better of someone

To gain the advantage over them; to outwit them.

Idiom: go one better than someone

To beat them by improving on what they have done, achieved or offered, etc.

Idiom: had better do something

Ought to do it, especially in order to avoid some undesirable outcome.
Example: I had better go now

Idiom: so much the better

That is, or would be, preferable.

Etymology: Anglo-Saxon betera; 14c as verb 2.