“Wyrd” (“Ƿyrd” if you’re picky about medieval spelling) is the Old English spelling of the word which is believed to have turned into the word “weird.” There’s no direct translation into modern English, but it generally carries the approximate meaning of fate, the inexorable progress of events, the march of time, etc. My copy of “A Concise Anglo-Saxon Dictionary” gives me “fate, chance, fortune, destiny, Providence, event, phenomenon, transaction, fact, deed, condition, pleasure.”
As one example, the line “Ƿyrd bið full aræd” from “The Wanderer” has been variously translated as “events always go as they must,” “fate never wavers,” etc., “gæ a ƿyrd sƿa hio scel” from Beowulf as “fate always goes as she shall,” and so on. You can see the connection in Macbeth “the weird sisters” as they foretell Macbeth’s fate.
Pearce writes an interesting essay, but I don’t think he’s using ƿyrd in the same way as it was in the literature of the period.