What is co-transport and why do I sometimes hear it being called active transport?

Example: absorption of sodium ions (Na+) and glucose by cells lining the ileum (a part of the small intestine)  1. Na+ actively transported into the blood from epithelial cells, by the sodium-potassium pump. 2. Creates a concentration gradient of Na+ - lower conc. of Na+ in epithelial cell than in lumen.) 3. Na+ and glucose move by facilitated diffusion into the epithelial cell from the lumen, via a co-transporter protein (glucose can move against its conc. gradient by using the conc. gradient of sodium.) 4. Creates a concentration gradient of glucose - higher conc. of glucose in epithelial cell than blood. 5. Glucose can move out of cell into blood by facilitated diffusion through a protein channel. Why is co-transport considered active transport? - Secondary active transport - Doesn't directly depend on ATP i.e. ATP is not directly involved in the functioning of the co-transporter - Instead, it relies on the ion gradient acquired by pumping ions in and out of the cell, by (primary) active transport