[ gdw]
The pir- stem confirms a link with Latin pirula, i.e. ‘tip or end of the nose’ – a diminutive of pirum, i.e. ‘fruit of the pear tree’ or ‘pear-shaped artefact’ (DMLBS 2290a). However, in that case the -un ending appears to be unetymological, and can only be explained though association with pinun, i.e. ‘pinnacle, summit’, another word used to refer to the’ tip of the nose’ (in some instances as a gloss to the same Latin pinula). Although it is not excluded that pirrun and puirrun are misreadings of, respectively, pinun and puinun, this exclusively Anglo-Norman word may be a genuine combination of the two etymologies.