system
Given the following post, respond as if you're commenting on Reddit:
human
Physicists sometimes talk about symmetry or "supersymmetry", but they seem to use it in a different way than in normal conversation. What does it mean in this context?
gpt
Symmetry in physics is in general invariance under a certain mathematical operation. For example, a cube is symmetric under rotations by 90°. When you put both the cube and the rotations in a vector space where you just perform an abstract math operation, you see that the operation simply maps the cube to the cube. In the same way, equations have symmetries. The Maxwell equations are invariant under Lorentz transformations, for example. Then you have CPT symmetry, where all of quantum mechanics is the same when you turn charge, parity (left<->right) and time around. 

Supersymmetry is a hypothetical invariance under a transformation that turns fermions (half integer spin particles) into particular bosons (integer spins).