Capitonym

A capitonym is a word that changes its meaning (and sometimes pronunciation) when it is capitalized, the capitalization usually applies due to one form being a proper noun or eponym. It is a portmanteau of the word capital with the suffix -onym. A capitonym is a form of homograph and – when the two forms are pronounced differently – also of heteronym. In situations where both words should be capitalized (such as the beginning of a sentence), there will be nothing to distinguish between them except the context in which they are used.