Notation (noun)

1. A system of signs or symbols used to represent something such as a number, musical notation, or mathematical formula.
2. A system of symbols used to represent something such as a quantity or a process, especially in mathematics or music.

Origin:

From the latin "notatio" meaning "marking, notation".

Examples:

1. She used a special notation in her math equations.
2. The notation of music is used to write down compositions.
3. The notation used to represent the mathematical formula was confusing.
4. He was familiar with the notation used in the scientific study.
5. The notation system used in the book was not clear.