sedimentar
sediment
sediment
matter that settles to the bottom of a liquid
+
-ar
verb suffix
Sedimentar means to sediment and can be thought of as sediment0 + -ar1. It's the action of matter settling to the bottom of a liquid0, formed into a verb1.
verb
  1. sediment
    To settle as sediment
    Las partículas comenzaron a sedimentar en el fondo del río. // The particles began to settle at the bottom of the river.