Definition that contains parallel line
- couple (physics) something joined by two equal and opposite forces that act along parallel lines
- ray a group of nearly parallel lines of electromagnetic radiation
- beam a group of nearly parallel lines of electromagnetic radiation
- parallel (mathematics) one of a set of parallel geometric figures (parallel lines or planes)
- alignment the spatial property possessed by an arrangement or position of things in a straight line or in parallel lines
- cylinder a surface generated by rotating a parallel line around a fixed line
- herringbone a pattern of columns of short parallel lines with all the lines in one column sloping one way and lines in adjacent columns sloping the other way; it is used in weaving, masonry, parquetry, embroidery
- t-square a square used by draftsmen to draw parallel lines
- vanishing point the appearance of a point on the horizon at which parallel lines converge
- electron beam a group of nearly parallel lines of electromagnetic radiation