How can tartar and plaque be removed from teeth without grinding? is there any paste, etc. for it?
The girders of a suspension bridge form an arc. The definition of an arc is a curve or bowed shape, like a part of a circle. An example of an arc is a rainbow. To arc is defined as to make a curved shape or move in a curved path.
envelope - a curve that is tangent to each of a family of curves. curve, curved shape - the trace of a point whose direction of motion changes. 4. envelope - a natural covering (as by a fluid); the spacecraft detected an envelope of gas around the comet covering, natural covering, cover - a natural object that covers or envelops; under a covering of dust; the fox was flushed from its cover