Feynman diagram

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A diagram used in quantum electrodynamics and quantum chromodynamics to help describe and visualize the possible interactions between particles. Fermions are represented with straight lines, and bosons with wavy lines. Points of intersection indicate an interaction between the particles.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun physics a pictorial representation of the interactions of subatomic particles, showing their paths in space and time as lines, and their interactions as points where lines meet