Part of the IT standards and organizations glossary: The Stefan-Boltzmann constant, symbolized by the lowercase Greek letter sigma (), is a physical constant involving black body radiation.A black body, also called an ideal radiator, is an object that radiates or absorbs energy with perfect efficiency at all electromagnetic wavelength s.art of the IT standards and organizations glossary: The Stefan-Boltzmann constant, symbolized by the lowercase Greek letter sigma (), is a physical constant involving black body radiation.
Definition of memoir for English Language Learners. memoirs : a written account in which someone (such as a famous performer or politician) describes past experiences.
Learner's definition of CHRONICLE. [+ object]. : to describe a series of events in the order that they happened. The book chronicles the events that led to the American Civil War. She intends to chronicle the broad social changes that have occurred in this part of the country. a magazine that chronicles the lives of the rich and famous. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.