the.com/convention
A handshake everyone agrees to without ever shaking hands.
means A widely accepted rule, practice, or agreement that people follow by mutual understanding rather than law.
from From Latin conventio, a coming together, from convenire, to assemble or agree — the same root that gives us convene and, fittingly, convenient.
Three livesMeans custom, gathering, and formal treaty all at once.
Driving proofWhich side of the road is pure convention.
French upheavalThe 1792 National Convention abolished the monarchy.