(engineering) Any linkage by which circular motion may be changed into motion in a straight line.

plural of parallel ruler

A geometrical instrument for drawing parallel lines.

A form of play involving two or more children doing an activity in the same room but without paying attention to one another. Primarily seen among children between the age of 6 months up to late preschool.

(geometry) A way of transporting geometrical data along smooth curves in a manifold.

plural of parallel transport

(Canada, US) A nickname for the approximately 1200-mile (1900-kilometer) portion of the border between Canada and the USA, extending along the forty-ninth parallel of latitude from Lake of the Woods to the Pacific Ocean.

(mycology) A gill trama that is not divided and whose cells are parallel in a cross section.

(uncountable, skiing) A discipline of alpine snowboarding, a variant of giant slalom. A sport where two snowboarders compete head to head on parallel identical giant slalom courses.

(physics) A theorem that states the moment of inertia of a rigid body about any axis is equal to its moment of inertia about a parallel axis through its center of mass plus the product of the mass of the body and the square of the distance between the two parallel axes.