I have been thinking lately that I need to define some terms for the parts of mechanical pencils, types of mechanisms and so on. I had a look at Wikipedia and suddenly realised that neither they, nor I, had a decent definition of “mechanical pencil”, so I thought I had better start at the beginning. A definition of mechanical pencil turned out to be harder than I expected. Intuitively I feel that it is any pencil where the lead is not an integral part of the pencil, where the lead is free to move around but is held in position by some mechanism or part of the pencil body.

My Definition of Mechanical Pencil

Mechanical Pencil – (noun) A device for writing or drawing in which the solid marking core (usually graphite based and called ‘pencil lead’, but coloured pigments and other solid substances are also used) is not bonded to the outer casing, and is designed such that the core is to be extended as its point is worn away.

Notes for clarification for the purpose of this definition:

A mechanical pencil is a writing or drawing device, thus mechanical pencil-like items that have a core of cosmetic product, medical product, a metal pointer, etc and are intended primarily for non-writing or drawing purposes are not mechanical pencils.

Mechanical pencils have a solid marking core and are thus distinct from pens and other markers which use a liquid or semi-solid marking material. An eraser core is not a marking core and thus pencil-like items with such cores are not mechanical pencils.

Multi function pens and other combination implements may include a component that is of itself a mechanical pencil, and thus they are mechanical pencils, as well as being something else.

Pop-a-point pencils are not mechanical pencils as their lead is not extended as it is worn down, it is replaced by a whole new piece of lead.


I believe my definition would include the things we normally think of as mechanical pencils, plus leadholders / clutch pencils, but would exclude woodcase and similar ‘standard’ pencils. Things get tricky out on the edges – items that have the shape of a mechanical pencil but are loaded with cosmetic or medical product, wax marker, soapstone or chalk, etc. Are they mechanical pencils or not. Generally I tend to think no they aren’t, but it’s very debatable, and it's hard to define. Take a Staedtler 925 25 20 loaded with a stick of HB lead. It’s a mechanical pencil, no question about it. Now take the stick of HB lead out and replace it with a stick of “Tropical Seduction” eyeliner. Erase Staedtler from the body and print “ManTrap” on it instead. Is it still a mechanical pencil? (FYI, this example isn’t that far from reality)

(Thanks to the folk who have commented on earler drafts of this)