There is a common misconception even among the elders on “the difference between letters and alphabets“ in English language. The thing is that we have 26 alphabets in English while we have 26 each defined letters i.e. “A” is a letter similarly “B” is a letter and so on . Summation of all letters gives us the alphabets.
So the conclusion is we have 26 alphabets and “A” so on are letters of the language.
Combination of letters which imply certain meaning are called “Words”.