Who coined the term "laughing gas" to describe nitrous oxide?

In 1799, a British inventor and chemist named Humphry Davy (17 December, 1778 - 29 May, 1829) started experiencing with nitrous oxide (a chemical compound) to know what the gas might do to people, and to find out he started inhaling it himself, recording the pleasant sensation. After experimenting with its inhaling effects on many others, he coined the term "laughing gas" due to its euphoric (pleasure, excitement and intense feelings of wellbeing and happiness) effects. He wrote about its potential anaesthetic (relief from or prevention of pain) properties. Nitrous oxide or laughing gas or happy gas is a colourless gas with pleasant, sweetish odour and taste, which when inhaled produces insensibility to pain preceded by mild hysteria, sometimes laughter.

During those times, no one thought to try it as a surgical anesthetic for almost 50 years. Instead, it became widely known for its entertainment value with opportunists staging public exhibitions. These took place in traveling medicine shows and carnivals. For a small fee, people could laugh and act silly while they breathed the intoxicating gas.

Today, nitrous oxide is routinely used alongside other anesthetic agents in operating rooms everywhere. It's also used as a mild sedative and analgesic during childbirth, for emergency medical care and for dental procedures.