Lettergram is a unique word that refers to a message that is sent in the form of a letter. However, there are several synonyms for the word that can be used in its place. For instance, epistle, dispatch, memo, note, missive, and correspondence are all excellent synonyms for lettergram. Other words that can be used include message, communique, bulletin, report, news, and announcement. All of these words convey the same meaning as lettergram and can be used interchangeably. Whether you are writing a letter, email, or instant message, these synonyms are great alternatives that add variety to your writing and make it more interesting.