An incorrect spelling; a spelling different from accepted spelling.(noun)
Spelling in which a particular letter represents more than one possible sound.(noun)
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Use "heterography" in a sentence
"The good mother -- had she not endeared herself to the modern reader by the affectionate gentleness and the quaint glimpses of domestic life that her family letters reveal -- would be irresistible by the ingeniously bad spelling in which she reveled, transgressing even the wide limits then allowed to feminine heterography."