1, groove, pronounced cáo, meaning a rectangular or square larger utensils to hold things, derived from the utensils used to hold fodder to feed livestock, groove-shaped things or the two sides of the high up, the center of the concave object of the concave part.

2, channel steel, cross-section for the groove-shaped long steel, belonging to the construction of carbon structural steel and mechanical steel, is a complex cross-section of the section of steel, the shape of its cross-section for the groove-shaped. Channel steel is mainly used in building structures, curtain wall engineering, mechanical equipment and vehicle manufacturing.