LDL cholesterol (low-density lipoprotein) is often called the "bad" cholesterol. It carries cholesterol to tissues, but when there's too much, it deposits in artery walls as plaque, narrowing and stiffening the arteries and raising the risk of heart attack and stroke.
For LDL, lower is generally better, though the right target depends on your overall cardiovascular risk and is set with a clinician — not a single universal number. Diet (less saturated fat, more soluble fiber such as oats), activity, and, when needed, statins can lower it. See how to lower cholesterol and high cholesterol in women.