In the case of mutual satellite events, such as the Jovian PHEMUs, an eclipse is when a satellite passes into the shadow of another satellite; an occultation is when one satellite passes in front of another satellite.
https://britastro.org/section_news_item/mutual-events-of-the-galilean-satellites-2026-27
“For a few months either side of equinox, the Galilean satellites are involved in mutual occultations (when one satellite passes behind another) and eclipses (when one satellite passes into the shadow of another). These events may be total, annular or partial.”
“Results from participating in PHEMU15” (3.5 MB PDF)
http://www.esop37.cz/sbor/L5-1_Pratt_lecture.pdf
Alex.