I am pretty sure its a line segment.
A straight line, a telephone line, a shipping line, a fishing line.
a line
In geometry a straight line that touches a curve is called a tangent.
There is no particular name.
Straight
There are quite a few websites that will help people with sewing patterns, tutorials and videos. To name a few, one could visit Learn Stitching. Churidar Sewing Techniques and Panmai.
Collinear lines lie on the same straight line.
straight line.
A Linear graph
Straight line
radius