propelling pencil

noun

a pencil consisting of a metal or plastic case containing a replaceable lead. As the point is worn away the lead can be extended, usually by turning part of the case

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012