Leptogenesis

Part of speech: noun

Definitions

1. The process describing the initial formation or origin of a slender or thin structure, often used in a scientific or biological context ; the emergence or creation of something narrow or fine ; the starting point or generation of a delicate or slim entity
2. An event or sequence leading to the birth or initiation of a tapered or slight form ; the commencement of something characterized by thinness or subtlety ; the cause or condition producing a lean or finely drawn object
3. The act or phenomenon by which a slim or faintly developed element comes into being ; the genesis or inception of a light or refined structure ; the development phase marked by the creation of a narrow or slight aspect

Etymology: "Leptogenesis" is a technical coinage, not an ancient word. It joins "lepto-", from Greek "leptos" meaning "thin, fine, slender" (the same root behind "leptospirosis" and "leptocephalus"), with "genesis", from Greek "genesis" meaning "origin, coming into being". Put together, the pieces mean roughly "the production of something fine or slight." The word's everyday sense is far narrower than the broad dictionary gloss suggests. In modern physics and cosmology it names a specific process: a hypothetical mechanism that could have produced the imbalance between matter and antimatter in the early universe by generating a surplus of leptons (particles such as electrons and neutrinos) before that excess was converted into the matter we see today. So a word built on the idea of something "slim" or "delicate" ended up describing one of the largest-scale events imaginable.