"point at which a planet or comet is nearest the Sun," 1680s, coined in Modern Latin (perihelium) by Kepler (1596) from Latinizations of Greek peri "near" (see peri-) + hēlios "sun" (from PIE root *sawel- "the sun"). Subsequently re-Greeked.
pericardium
Pericles
pericope
peridot
perigee
perihelion
peril
perilous
perimeter
perinatal
perineum