Try Our Apps
The Word of the Year is...
A theorem of physics, stating that for every case of invariance in a physics, there exists a unique conservation law, and for every conservation law, there exists a unique invariance.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Discover our greatest slideshows
8 Offbeat Literary Genres to Get...
Decode the pieces of our favorite...
Know These 9 Commonly Confused...
Uncover the mysteries of the marks...
Browse more topics on our blog
What Is the Difference Between Discreet and Discrete?
Learn the correct uses of these two commonly confused homophones.
What Character Was Removed from the Alphabet?
What mistaken pronunciation gave this character its name?
This small mark has two primary uses: to signify possession or omitted letters.
How Do I Get a Word into the Dictionary?
People invent new words all the time, but which ones actually make it?
Word of the Day
Word Value for
Words With Friends
Nearby words for noether's theorem
Piece of cake?