Best is used to form the superlative of compound adjectives beginning with `good' and `well'. For example, the superlative of `well-known' is `best-known'. see also second best, Sunday best
the supreme effort one can make; "they did their best" the person who is most outstanding or excellent; someone who tops all others; "he could beat the best of them" Canadian physiologist (born in the United States) who assisted F
You use best of all to indicate that what you are about to mention is the thing that you prefer or that has most advantages out of all the things you have mentioned. It was comfortable and cheap: best of all, most of the rent was being paid by two American friends
If someone does something as best they can, they do it as well as they can, although it is very difficult. The older people were left to carry on as best they could
If you do your best or try your best to do something, you try as hard as you can to do it, or do it as well as you can. I'll do my best to find out It wasn't her fault, she was trying her best to help