Here's the background: in QED, there is one charge, which we're all familiar with, the electric charge. Mathematically we can call the charge C, such that using + to denote its regular charge and - to denote its anticharge:

[eqn]C^+ + C^- = 0[/eqn]

In other words, a charge added to its corresponding anticharge yields 0 charge, or neutral. Compactly, we just call these charges [math]+[/math] and [math]-[/math]. Moving on to QCD, we have three charges which function in the following way:

[eqn] \begin{align}

C_1^+ + C_1^- &= 0 \\

C_2^+ + C_2^- &= 0 \\

C_3^+ + C_3^- &= 0 \\

C_1^+ + C_2^+ + C_3^+ &= 0 \\

C_1^- + C_2^- + C_3^- &= 0

\end{align}

[/eqn]

Where the first three equations represent simple mesons, which follow the rules we expect: charge plus anticharge equals neutral. The last two equations represent baryons, with the first representing real baryons and the second being anti-baryons. Now three "positive" charges yield a neutral charge.

Feynman called these physicists idiots for calling it color. What say you, /sci/? Any better names?