I guess scientists figured that, since the word, "hydrogen" starts with an "H", why not use it?
H is the symbol
The symbol for hydrogen on the periodic table is H.
The chemical formula (not symbol) for hydrogen chloride is HCl.
The symbol for hydrogen is H, and the symbol for helium is He.
The letter H is the chemical symbol for the element hydrogen.
The symbol for hydrogen sulfide is H2S.
Hydrogen carbonate is a compound, not an element, and it therefore has a formula, not a symbol: H2CO3.
The symbol for Hydrogen iodide is HI.
H2O2 is the chemical formula. Since hydrogen peroxide is not an element it does not have a symbol.
The hazard symbol you should find on a container of hydrogen is a flame symbol indicating that hydrogen is highly flammable.
The chemical formula for hydrogen sulfide is H2S.
The symbol for hydrogen gas is H2