some words from French, Latin or Greek end with a consonant followed by an unstressed -re (pronounced ). In modern American English, most of these words have the ending -er. The difference is most common for words ending in -bre or -tre: British spellings ''[[wikt:calibre all have -er in American spelling.

In the United Kingdom, both -re and -er spellings were common before Johnson's 1755 dictionary was published. Following this, -re became the most common usage in the