- Today's Word
Accretion
uh-KREE-shun
Definition
(noun) Growth or increase by the gradual accumulation of additional layers or matter.
Example
The planet formed through accretion as dust and gas particles slowly clumped together over millions of years.
Word Origin
Early 17th century: from Latin “accretio(n-),” from “accrescere” meaning “to grow,” from “ad-” (to) + “crescere” (to grow).
Fun Fact
Accretion explains how planets, pearls, and your retirement savings all grow—through gradual addition rather than sudden creation. Astronomers use accretion disks to describe how matter spirals into black holes, adding mass bit by bit. Oysters create pearls through accretion, coating irritants with layer upon layer of nacre. Financial advisors love the term for describing compound interest’s power. While “accumulation” works similarly, accretion specifically emphasizes the layering process—each addition building on what came before. The Antarctic ice sheet grows by accretion as annual snowfall compresses into new ice layers, preserving ancient atmospheric bubbles like geological time capsules.