Word

hydrogen

noun C1

/ˈhaɪdɹəd͡ʒ(ə)n/

Meanings

noun

a chemical element (H), the lightest element, usually a colorless, very flammable gas

noun

hydrogen used as a fuel or energy carrier, especially for powering vehicles or producing electricity

Definition

Hydrogen is the lightest chemical element, a colorless gas that is highly flammable and common in water and many compounds.

Hydrogen is a chemical element with the symbol H and the smallest, lightest atoms of any element. In its usual form on Earth, it is a colorless, odorless gas that can burn easily when mixed with oxygen. Hydrogen is a basic building block of water and many other substances, and it is also used as an industrial fuel and raw material.

Examples

In the experiment, I collected hydrogen in an upside-down jar to keep it from mixing too quickly with air.
You can generate hydrogen through electrolysis, but you must handle the gas with strict safety precautions.
The engineer explained how hydrogen embrittlement can weaken certain metals over time.
She traced the peaks on the spectrum and identified hydrogen as the simplest reference point.
They debated whether hydrogen will scale fast enough to support heavy industry as well as transport.

Common mistake

Learners sometimes confuse hydrogen (the element) with water, but water is a compound made from hydrogen and oxygen.