h

Multiple Entries:
  h    H    hydrogen  

Concise Oxford English Dictionary © 2008 Oxford University Press:
h/eɪtʃ/

▶abbreviation

• 1 (in measuring the height of horses) hand(s).

• 2 hecto-.

• 3 Brit. (with reference to sporting fixtures) home.

• 4 horse.

• 5 hot.

• 6 hour(s).

▶symbol Physics Planck's constant.

Concise Oxford English Dictionary © 2008 Oxford University Press:
H1 (also h)

▶noun (pl. Hs or H's)

• 1 the eighth letter of the alphabet.

• 2 denoting the next after G in a set of items, categories, etc.

• 3 (H) Music (in the German system) the note B natural.

Concise Oxford English Dictionary © 2008 Oxford University Press:
H2

▶abbreviation

• 1 (of a pencil lead) hard.

• 2 height.

• 3 Physics henry(s).

• 4 informal heroin.

• 5 Hungary (international vehicle registration).

• 6 Brit. (on street signs) hydrant.

▶symbol

• 1 Chemistry enthalpy.

• 2 the chemical element hydrogen.

• 3 Physics magnetic field strength.

Concise Oxford English Dictionary © 2008 Oxford University Press:
hydrogen /ˈhʌɪdrədʒ(ə)n/

▶noun a colourless, odourless, highly flammable gas, the chemical element of atomic number 1. (Symbol: H)

– derivatives
hydrogenous /-ˈdrɒdʒɪnəs/ adjective.

– origin C18: coined in Fr. from Gk hudro- ‘water’ + -genēs (see -gen).