| Answer | Crossword Clue |
|---|---|
| envelopes | A curve or surface tangent to each of a family of curves or surfaces |
| trajectories | A curve or surface cutting a family of curves or surfaces at a constant angle |
| trajectory | A curve or surface cutting a family of curves or surfaces at a constant angle |
| envelope | curve tangent to each of a family of curves |
| envelope | surface tangent to each of a family of surfaces |
| osculates | (of a curve or surface) Touch (another curve or surface) so as to have a common tangent at the point of contact |
| osculating | (of a curve or surface) Touch (another curve or surface) so as to have a common tangent at the point of contact |
