An Elementary Particle which makes up the Neutron and the Proton, as well as many more exotic particles. These particles are Fermions, and have charges of either 2/3 as much as an electron's charge, or -1/3. They come in "flavors" of up, down, strange, charmed, bottom, and top, as well is in "colors" of red green and blue. The "flavor" and "color" are just fanciful names given to describe intrinsic properties of these particles — similar to charge, mass, or spin.
Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run twice as fast as that.
The Red Queen in Lewis Carroll's Through the Looking Glass