the unit h is referring to height or the planck constant ze
It depends on the context - there are no rules that say that a particular letter must always have a particular meaning.
Oh, I thought they were meaning H, the Magnetic Field Intensity.
Any Science publication should be expected to define the symbols - except when the context is extremely obvious.
h is the usual symbol for the Planck constant.
h=6.62606957 × 10-34 m2 kg / s
Most letters can have multiple meanings in different problems. There are not enough letters for all physical concepts.
Separate names with a comma.