Letter as in A, B, C, D, ect? If that is the case, then another name for letter is "Character"
they are different
they are different
they are different
they are different
a note that has the same pitch but a different letter name
Barbara
Different species have different names that start with different letters. However, all species names are generally preceded by a genus name.
Barbara
enharmonic = a different letter name for the same key C flat.
120
91.5% approx. Most of the rest have a symbol which starts with the first letter of the element's Latin name.
Playing 3 different notes at the same time is a chord.