1. hard.
2. Gram. head.
3. Elect. henry.
4. Slang. heroin.
5. high.
Symbol.
1. the eighth in order or in a series.
2. ( sometimes l.c. ) the medieval Roman numeral for 200. Cf. Roman numerals .
3. Chem. hydrogen.
4. Biochem. histidine.
5. Physics.
a. enthalpy.
b. horizontal component of the earth's magnetic field.
c. See magnetic intensity .
6. Music. the letter used in German to indicate the tone B.
H 1
Symbol, Chem.
protium.
Also, 1 H, H a .
H 2
Symbol, Chem.
deuterium.
Also, 2 H, H b .
H 3
Symbol, Chem.
tritium.
Also, 3 H, H c .