Words: grist, n. and v.

ANY EDITOR rightly strikes out the phrase "grist to the mill" as a cliche - and those that use it most likely have little idea what grist can be. Johnson defines it as "corn to be ground". It was first used in the 15th century, from the Old English, but it had originally been the act of grinding rather than what was ground.

It might not seem strange that in Anglo-Saxon times it should also have meant the grinding of teeth, but, for all the similarity of action between mouth and mill, it is probable that the former derives from the German (in which it also means a peevish person), and survived in that sense in Wiltshire until the last century.

That it should also be a size of yarn might seem less obvious, but that is derived from gird.