hydrogen

noun hy·dro·gen \ˈhī-drə-jən, -dər-\

: a chemical element that has no color or smell and that is the simplest, lightest, and most common element

Full Definition of HYDROGEN

: a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis — see element table — compare deuterium, tritium

— hy·drog·e·nous \hī-ˈdrä-jə-nəs\ adjective

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Origin of HYDROGEN

French hydrogène, from hydr- + -gène -gen; from the fact that water is generated by its combustion

First Known Use: 1788

HYDROGEN Defined for Kids

hydrogen

noun hy·dro·gen \ˈhī-drə-jən\

Definition of HYDROGEN for Kids

: a colorless, odorless, and tasteless flammable gas that is the lightest of the chemical elements

Word History of HYDROGEN

When hydrogen is burned it combines with oxygen to make water. That fact accounts for the name of this gas. The word hydrogen was formed from two Greek roots. The first, hydro-, means “water,” and the second, -gen, means “giving rise to, producing.”

Medical Dictionary

hydrogen

noun hy·dro·gen \ˈhī-drə-jən\

Medical Definition of HYDROGEN

: a nonmetallic element that is the simplest and lightest of the elements and that is normally a colorless odorless highly flammable diatomic gas—symbol H; see deuterium, tritium; element table

—hy·drog·e·nous \hī-ˈdräj-ə-nəs\ adjective