Burr

[…] nay Friar, I am a kind of Burre, I ſhal ſticke.

But cockle, spurge, according to their law / Might propagate their kind, with none to awe, / You'd think; a burr had been a treasure trove.

You left a bunch of burrs on those parts yesterday. You've already been told not to miss the deburring operation.

But the graver, in ploughing furrows in the surface of the copper, raises corresponding ridges or burrs

And there kyng Arthur smote syr mordred vnder the shelde wyth a foyne of his spere thorughoute the body more than a fadom / And whan syr Mordred felte that he had hys dethes wounde / He thryst hym self wyth the myght that he had vp to the bur of kynge Arthurs spere / And right so he smote his fader Arthur wyth his swerde holden in bothe his handes

burr or ring of iron behind the hand

The front of it was defended by an iron-plate, called a vam-plat, that is, an avant-plate, and behind it was a broad iron ring, called a burr.

We are made to witness a cathartic shuffling-off of mortalities and of hatreds: Mordred's pulling himself up to the 'burr' of Arthur's spear is Malory's own detail and one of the most memorable in the book.