This element, once widely used in plumbing is known in Latin as plumbum, hence its symbol Pb
Why is ... [PAR] There are multiple reasons for this.Some of them can be explained easily: 
Prehistorically it was ... Prehistorically it was named Plumbum and hence came 
its symbol Pb,much like ... commonly used for other meanings which are "Latent 
Heat","Internal Energy" ...