(music) Tonic, or the first scale degree.
Of telephone numbers dialed in North America, having an additional charge assessed to the caller, part of which is returned to the owner of the number.
(North America) A toll-free number or a long-distance telephone numbers; using any of North American toll-free area codes 800, 888, 877, 866, or 855.
Origin of 1
1, used to dial long-distance numbers + 800, which was, for a long time, the only North American toll-free area code
1, used to dial long-distance numbers + 900, the North American premium charge area code