“Penny-farthing”
What it means
The high-wheeled Victorian bicycle.
Where it comes from
The machine has an enormous front wheel and a tiny rear one. Set a penny beside a farthing and you have the profile exactly, which is how the bicycle came to be named after two coins.
How sure are we?
Attested, though retrospectively: the name was applied in the 1890s, after the design had already been superseded by the safety bicycle. Contemporaries called it the ordinary.