serrated knife [ser-ey-tid, suh-rey– nahyf] noun
A specialized knife that has a notched edge with saw-like teeth as seen in the bottom of this image.
Many bakers like to torte their cakes using a serrated knife but we find that the ridged edge dredges up crumbs, which create havoc when you are trying to apply frosting smoothly. We prefer to use a hollow-edge slicing knife, as seen in top of image. Read How to Level Your Cake Layers for a more in-depth explanation.