Lunesta

Part of speech: noun

Definitions

1. A prescription sedative tablet sold under a brand name, used to treat difficulty falling asleep and staying asleep
2. The trade name of a hypnotic drug prescribed for short-term relief of insomnia by slowing activity in the brain
3. A branded sleeping pill, containing the active ingredient eszopiclone, prescribed to help adults who struggle with insomnia

Etymology: Lunesta is a brand name, not a word that grew organically from older English, so its history is a matter of corporate naming rather than linguistic drift. It is the proprietary name for eszopiclone, a sleep medication, and it belongs to a family of invented pharmaceutical names built to be short, pronounceable and unlike any existing word. The name seems to draw on the Latin "luna", meaning moon, probably to suggest night-time rest. Drug names of this kind are typically assembled by marketing and naming firms, which combine sounds and syllables, check them against trademark databases and clinical concerns, and then register them. The moon association is a reasonable reading of the name's shape, though the company's exact reasoning is not something I can confirm. Because it is a trademark, the word is capitalised and used as a noun for the product. Generic speech tends to rely on the active ingredient instead, eszopiclone, which is the name a pharmacist or doctor is more likely to use.