Piano ends with O. why does it add s when it becomes plural? Does it belong to the case that the ending is vowel + O?

Piano ends with O. why does it add s when it becomes plural? Does it belong to the case that the ending is vowel + O?

The English word ending with O means something with life, plus es
For inanimate, add s, such as potatoes and photos
Some people say that remember the hero potato, tomato, black after ES can be