Ruis

Ruis can mean:


 * Ruis (letter), a letter of the Ogham alphabet
 * Ruis, Switzerland, a kreis in Switzerland
 * the municipality of Rueun in Switzerland, formerly known as Ruis
 * Rye, which translates to "ruis" in the Finnish language
 * RUIS acronym of Revolutionary Union for Internationalist Solidarity, an anarchist militia in the Syrian Civil War.