giant star definition by American Heritage Dictionary
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Any of a class of highly luminous, exceptionally massive stars.
giant star - Science Definition
A very large, bright non-main-sequence star that burns hydrogen at a much faster rate than a dwarf star. Giant stars are much more luminous and have shorter lifespans than the slower-burning dwarfs. The larger the giant, the shorter its lifespan; the largest stars, with solar mass of around 100, blaze at several hundred thousand times the energy of the Sun and will last only a few million years, a very brief time when compared with the Sun's 10-billion-year lifespan. Giant stars usually end their lives as supernovae , but even before that event the immense ultraviolet radiation they produce has a dramatic impact on their stellar surroundings; the presence of a giant star in a star system prevents the formation of new protostars because the radiation from the giant star breaks apart any nearby nebulae.