hydrogen air
A mixture of hydrogen and air used as fuel to a fuel cellA mixture of hydrogen and air used as fuel to a fuel cell.
Meaning
2 senses(uncountable)A mixture of hydrogen and air used as fuel to a fuel cell.
(obsolete, uncountable)An early term for hydrogen; hydrogen gas.
Lessons for this word
1 lessons- A1Countable and uncountable nouns — Because it can be uncountable