User:JackLumber~enwiktionary/-re / -er

Etymology
In British usage, some words of French, Latin, or Greek origin end with a consonant followed by -re, with the -re unstressed and pronounced. Most of these words have the ending -er in the U.S. The difference is most common for words ending -bre or -tre: British spellings accoutre(ment), goitre, litre, lustre, mitre, nitre, reconnoitre, saltpetre, spectre, centre, titre; calibre, fibre,  sabre, and sombre all have -er in American spelling. The ending -cre, as in acre, lucre, massacre, mediocre, is preserved in American English, to indicate the c is pronounced rather than. After other consonants, there are not many -re endings even in British English: louvre, manoeuvre after -v-; meagre, ogre after -g-; euchre, ochre, sepulchre after -ch-. In the U.S., ogre and euchre are standard; manoeuvre and sepulchre are usually maneuver and sepulcher; and the other -re forms listed are variants of the equivalent -er form.

Derivatives and inflected forms
The e preceding the r is retained in U.S. derived forms of nouns and verbs, for example, fibers, reconnoitered, centering, which are, naturally, fibres, reconnoitred and centring respectively in British usage. It is dropped for other inflections, for example, central, fibrous, spectral. However such dropping cannot be regarded as proof of an -re British spelling: for example, entry derives from enter, which has not been spelled entre for centuries.

The difference relates only to root words; -er rather than -re is universal as a suffix for agentive (reader, winner) and comparative (louder, nicer) forms. One consequence is the British distinction of meter for a measuring instrument from metre for the unit of measurement. However, while poetic metre is often -re, pentameter, hexameter, etc. are always -er.

Exceptions
Many other words have -er in British English. These include Germanic words like anger, mother, timber, water, and Romance words like danger, quarter, river. Some -er words, like many -re words, have a cognate in Modern French spelled with -re: among these are December, diameter, disaster, enter, letter, member, minister, monster, number, oyster, powder, proper, sober, tender.

Theater is the prevailing American spelling and is used by America's national theater as well as major American newspapers such as the New York Times (theater section) to refer to both the dramatic arts as well as to buildings where performances take place; yet theatre is also current, witness Broadway and The New Yorker. In American English, theatre is particularly common in the two aforementioned uses. Some places in the United States have "Centre" in their names, named both before and after spelling reform, and there are very occasional uses of "Center" in England ).

More recent French loanwords retain an -re spelling in American English. These are not exceptions when a French-style pronunciation is used ( rather than ), as with double-entendre, genre, or oeuvre. However, the unstressed pronunciation of an -er ending is used more or less frequently with some words, including cadre, macabre, maître d', Notre Dame, piastre, and timbre.

Canada and Australia
The -re endings are standard throughout the Commonwealth. The -er spellings are recognised, as minor variants, only in Canada.