/ prɪˌsɪpɪˈteɪʃn; NAmE / noun
[ U ] ( technical ) rain, snow, etc. that falls; the amount of this that falls :
an increase in annual precipitation
[ U , C ] ( chemistry ) a chemical process in which solid material is separated from a liquid
late Middle English (denoting the action of falling or throwing down): from Latin praecipitatio(n-) , from praecipitare throw down or headlong, from praeceps , praecip(it)- headlong, from prae before + caput head.