t.d.s. means ter die sumendum - three times a day in Prescription
Similar to t.d.s.
nebul - nebula - a spray noct. - nocte - at night non rep. - non repetatur - no repeats NS - normal saline 0.9% o.p.d. - once per day o.s. - oculus sinister - left eye o.u. - oculus uterque - both eyes