A plane curve generated by the locus of the point at which a variable tangent to a rectangular hyperbola intersects a perpendicular from the center to the tangent. Equation: r 2=2a2cosθ.
Or... y'know.. one of these:
Latin, lēmniscātus - adorned with ribbons.
Thoroughly confusing his readership with mathematical wizardry, nerdfury decided it was easierr to just show everyone what a lemniscate was, thereby providing everyone with a new word they could slip into sentences. Remember, though: It's not okay to say "I could totally eat at this burger place for lemniscate!" or "Snap bracelets and rhinestone-studded denim jackets will never go out of style - they'll live on for lemniscate!"
It is, however, to use the word in those ways if the person you're talking to is too stupid to pick up on it!