H
n 1: a nonmetallic univalent element that is normally a colorless
and odorless highly flammable diatomic gas; the simplest
and lightest and most abundant element in the universe
[syn: hydrogen, atomic number 1]
2: a unit of inductance in which an induced electromotive force
of one volt is produced when the current is varied at the
rate of one ampere per second [syn: henry]
3: the constant of proportionality relating the energy of a
photon to its frequency; approximately 6.626 x 10\-34
joule-second [syn: Planck's constant]
4: the 8th letter of the Roman alphabet
5: (thermodynamics) a thermodynamic quantity equal to the
internal energy of a system plus the product of its volume
and pressure; "enthalpy is the amount of energy in a
system capable of doing mechanical work" [syn: heat
content, total heat, enthalpy]