A capitonym is a word that’s meaning, and sometimes pronunciation, changes when it is capitalized.

Here are some examples:
march= a manner of walking
March= the month of the year

may= can
May= the month of the year

Cuban= related to the country Cuba
cuban= related to cubes

Lent= the period between Ash Wednesday and Easter
lent= to lend

Polish= from Poland
polish= to create a shiny suface by rubbing against