A curve or surface which is tangent to each member of a system of curves or surfaces, the form and position of the members of the system being allowed to vary according to some continuous law. Thus, any curve is the envelope of its tangents.

The outermost points traced out by a moving curve.

The envelope of any function is the smooth curve passing through the peaks of the function

a curve that is tangent to each of a family of curves

a curve or surface that touches a whole family of other curves or surfaces like the wavelets

a curve that bounds another curve or set of curves, as the modul

a free form curve around an object

a mathematical curve , surface , or higher dimensional object defined as being tangent to a given family of lines or curves (or surfaces, or higher dimensional objects, resp

a piecewise linear curve defined by the end points of linear segments

In mathematics, an envelope of a family of manifolds (especially a family of curves) is a manifold that is tangent to each member of the family at some point.