Butterscotch is a type of confection whose primary ingredients are brown sugar and butter.
Butterscotch is similar to toffee, but the sugar is boiled to the soft crack stage, not hard crack.
The term "butterscotch" is also often used more specifically for the flavour of brown sugar and butter together, even if the actual confection butterscotch is not involved.
One explanation is the meaning "to cut or score" for the word "scotch", as the confection must be cut into pieces, or "scotched", before hardening.
Alternatively, the "scotch" may derive from the word "scorch".
In 1855, F. K. Robinson's Glossary of Yorkshire Words explained Butterscotch as "a treacle ball with an amalgamation of butter in it".
An 1848 issue of the Liverpool Mercury gave a recipe for "Doncaster butterscotch" as "one pound of butter, one pound of sugar and a quarter of a pound of treacle, boiled together".