Why is a pencil called a pencil?

In ancient times,there was a writing material called "lead powder"(not elemental lead powder,nor the white lead powder used for painting or women's cosmetics;that one was white while this one was black),and there is an idiom "carrying lead and holding wooden writing boards".Ancients wrote on wooden slips,and "qian" referred to blank wooden slips before writing.This idiom means carrying writing tools around to jot down inspirations and articles anytime needed.Pens used to write with lead powder were named "lead powder pens" or simply "pencils".In the Southern Liang Dynasty,Ren Yansheng wrote in Petition for Fan Shixing to Request a Monument for the Grand Minister:"Every household stores oiled paper and keeps pencils at hand."

Later,western graphite pencils were introduced into China.People adopted the old term to name this newly imported similar object,calling it "pencil" as well.The graphite inside was also named "black lead" because it resembled the black lead known to Chinese.These are all examples of naming new things by borrowing existing terms.