Grammatically, dual refers to a sense of number between singular and plural. Examples are the English word both, the Latin words duo and ambo (two and both), the familiar plural form in Icelandic, and various elements in Ancient Greek. Most languages have phased dual number out as it tends to be a confusing element in grammatical structure. Certain disappearing languages on the Pacific Rim are known to have a separate grammatical number for threes of things, too.