A crater on the Moon that lies within the strip of highland that rises between Mare Serenitatis to the north and Mare Tranquillitatis to the south. Although not particular large in comparison with other lunar craters (it is a little over forty kilometres in diameter) Plinius stands out prominently on the border between the two seas. It takes its name from Pliny the Elder (or Gaius Plinius Secundus), the Roman author and polymath who met his end while investigating the volcanic disaster at Pompeii.
Plinius has a ridged and terraced inner wall that descends downwards for some 2.3 km to the crater floor. The floor itself varies in terrain, smooth to the east, but rougher and more undulating to the west. In the centre of the crater (as is common) there is a central peak, though in Plinius this is an irregular height with a pair of summits. To the north of the crater, an east-west system of rilles runs nearby, and these also take their name from Plinius, being designated the Rimae Plinius.