Genu refers to an abrupt flexure or bend/angle in an anatomical structure, especially the bend in the anterior part of the corpus callosum. It can also be used to describe specific conditions like "genu valgum" (knock knee) or "genu varum" (bow leg). For instance, "genu valgum" is a condition where the knees touch each other when standing due to excessive inward angulation of the femurs, while "genu varum" is a condition where the knees are abnormally apart due to outward angulation of the femurs.