The term RADIOACTIVITY, MEASURE OF can be summarized as the measurement of radioactivity, which is the emission of energy in the form of particles or electromagnetic waves from an unstable atomic nucleus. The term is often associated with Marie CURIE, a Polish-born French physicist and chemist who was the first woman to win a Nobel Prize and the only person to win two Nobel Prizes in different sciences. Her surname, CURIE, is a 5-letter word that is related to this term.