English Language Subtleties

Spelling
In 1912, Anna Jarvis trademarked the phrases "second Sunday in May" and "Mother's Day", and created the Mother's Day International Association.[5][6]

She was specific about the location of the apostrophe; it was to be a singular possessive, for each family to honour their mother, not a plural possessive commemorating all mothers in the world.[5]

This is also the spelling used by U.S. President Woodrow Wilson in the law making official the holiday in the U.S., by the U.S. Congress on bills,[7][8] and by other U.S. presidents on their declarations.[9]

Common usage in English language also dictates that the ostensibly singular possessive "Mother's Day" is the preferred spelling, although "Mothers' Day" (plural possessive) or "Mothers Day" (plural non-possessive) are sometimes used.

MurielB a écrit:... considéré comme un adjectif, donc invariable.

Pourquoi donc Mothers day avec un s. Les deux premiers sont des cas possessifs donc il n'y a pas de problème. Merci de m'éclairer.

With titles, you may think of the word in front of the noun as either singular, plural, or possessive. For example, do you think of the holiday as belonging to each mother individually (Mother’s Day) or to all mothers collectively (Mothers’ Day)? Or do you think of the word Mothers as an adjective describing Day? There is no right or wrong answer to this question.

In most countries, Mother's Day is a recent observance derived from the holiday as it has evolved in America. When it was adopted by other countries and cultures, it was given different meanings, associated to different events (religious, historical or legendary), and celebrated on a different date or dates.

Some countries already had existing celebrations honoring motherhood, and their celebrations have adopted several external characteristics from the US holiday, like giving carnations and other presents to your own mother.

The extent of the celebrations varies greatly. In some countries, it is potentially offensive to one's mother not to mark Mother's Day. In others, it is a little-known festival celebrated mainly by immigrants, or covered by the media as a taste of foreign culture.