Refers to a drawing made primarily of lines, or the technique of drawing with lines, as opposed to painting or shading. Common in art and illustration contexts.
この絵本は線描だけで描かれている。
This picture book is drawn only with line drawings.
彼は線描
He excels at the technique of line drawing.
Compound of 線 (line) and 描 (draw, sketch). The reading びょう is the kan'on reading of 描.