The lemniscate $x^4-x^2+y^2=0$ was discussed in Gerono's <A HREF="https://archive.org/details/gomtrieanalytiq00gerogoog">Géométrie Analytique</A> from 1854, see screenshot, while Lissajous's "Mémoire sur l'étude optique des mouvements vibratoires" is from 1857.

<IMG SRC="https://ilorentz.org/beenakker/MO/Gerono.png"/>

The book <A HREF="https://books.google.nl/books?id=CWazJtSI2L0C&pg=PA172&lpg=PA172">Le curve matematiche tra curiosità e divertimento</A> notes that Cramer (1750) called the curve $(y+ax^2)^2=x^2-x^4$, a *Quersackcurve*, in latin *bisaccium* (a <A HREF="https://de.wikipedia.org/wiki/Quersack">Quersack</A> is a type of backpack). It is also stated that A. Aubry gave the $a=0$ curve the name lemniscate of Gerono in honor of his friend and colleague Camille Christophe Gerono. (I have not been able to locate Aubry's "Essai sur l'histoire de la géométrie des courbes".)