The teacher ringed out the wrong spellings with a red pencil.
This word has two spellings.
Webster's purpose in writing it was to show that the American language was developing different meanings, pronunciations, and spellings from those of the English language.
I know a lot of young kids use weird spellings like "b4" instead of "before." but if you notice, it's only those young kids who do that.
Afterwards Americans wondered why the British spelled things so strangely, and the British looked down their noses at the improper American spellings.