o-ring in English dictionary O-ring Meanings and definitions of "o-ring" A circular gasket, usually made of rubber. noun A circular gasket, usually made of rubber. more Grammar and declension of o-ring O-ring ( plural O-rings) O-ring (plural O-rings) more o-ring Sample sentences with "o-ring" Declension Stem Try again Available translations Amharic Arabic Dutch French German Hungarian Irish Italian Japanese Latvian Polish Portuguese Russian Spanish Tamil Authors