Cymbal and symbol are homophones. It tends to be symbol that is used when cymbal would be appropriate rather than the other way round; I suspect that is because symbol is simply more familiar. I also find cymbal is sometimes misspelt as cymbol (I haven’t been able to find any sources that accept cymbol as a legitimate alternative spelling, but I would be interested to hear from anyone who has such a source).

Cymbal

• a slightly concave, round brass plate which is struck against another or with a stick to produce a sound

Symbol

• a mark, shape, sign, figure or character used as a conventional representation of an object, quantity, function, process or organisation
• a thing that stands for or represents something else

My tip: cymbals are used when producing music.