pencil [ME] Although it looks as if pencil should come from *pen, the words are unrelated. A pencil once meant a fine paintbrush—Johnson’s dictionary defines it as ‘a small brush of hair which painters dip in their colours’. It comes from Old French pincel, from Latin penicillum ‘paintbrush’, from penis ‘tail’, from the tuft of hair at the end of some tails. The Latin penis was also used for the male organ, a use that passed into English in the late 16th century. Penicillum was also the source of the name of the drug penicillin [M20th] named from the brush-like shapes of the spore containers.