Example sentences
wǒ我yòng用qiān铅bǐ笔xiě写zì字。
I write with a pencil.
zhè这zhī支qiān铅bǐ笔shì是wǒ我de的。
This pencil is mine.
About this word
铅 is "lead" and 笔 is "writing tool", so 铅笔 is a lead pen, named after the grey mineral early pencils used, which was taken for lead. The modern core is graphite and holds no lead at all, but the name stuck. 笔 covers every writing instrument: 钢笔 (pen, "steel pen"), 毛笔 (brush, "hair pen"), 圆珠笔 (ballpoint). 铅 keeps its metal sense elsewhere, as in 铅笔盒, the pencil case that every Chinese schoolchild carries.
The story behind the character
铅
铅 is 钅 (metal) with 㕣 on the right giving the sound. Xu Shen's gloss is a small gift: 鉛，青金也, lead is the green metal. Fresh lead is grey, but it tarnishes to a dull blue, and that is the color the ancients caught. The "lead" in a pencil is really graphite, but the name came from this metal.
笔
笔 is 竹 (bamboo) over 毛 (hair). A bamboo handle with hair at the tip, which is a writing brush, drawn so plainly you need no help to read it. The traditional 筆 had 聿 instead, a hand holding a brush. Somebody along the way swapped the hand for the hair, and the character got more literal.