Anaesthesiology, is a branch of medicine that allows safe usage of medical drugs to induce a reversible state of total or partial lack of responsiveness to surgical procedures, so that they can be carried out smoothly, without causing any distress and inconvenience to the patient. 

The term Anaesthesia is derived from the Greek words ‘an’ meaning ‘without’ and ‘aesthesis’ meaning ‘sensation’. Thus, anesthesia literally means ‘without sensation’.