In making a final (one fervently hopes) revision pass through my second novel, I came upon a word that had been flagged by both my exacting editor and my document program: waybread.
First, I looked it up on Merriam-Webster, and found this:
way·bread
noun \ˈwāˌbred\
Definition of 
WAYBREAD
  Brit
: broad-leaved plantain 1
Origin of 
WAYBREADME 
weybrede, fr. OE 
wegbrǣde; akin to MD 
wegebrede broad-leaved plantain, OHG 
wegabreita; all fr. a prehistoric WGmc compound whose first constitutent is represented by OE 
weg way and whose second constituent is akin to OE 
brād broad; fr. its broad leaves and the fact that it frequently grows by the wayside — more at 
way, 
broadA plantain? Really? That was a surprise. The roots of the word are somewhat what I had in mind when I used it, but I wasn’t thinking of a plantain, for certain, which means I misused this oh-so-intriguing word. But where did I get it from then? What dark corner of my convoluted brain offered that word up at that moment in my writing?
Probably some game term, I mutter at myself reproachfully as I Google it. And Wikipedia helpfully informs me:
Waybread may refer to:
  Lembas
, a special food made by the Elves in J.R.R. Tolkien’s books
  Plantago major
, a plant
Ah, Tolkien. An unconscious borrowing, then. A pity. I shall have to replace it with some mundane word of lesser lineage.
But I’m grateful for the journey it took me on, and I have a new “true” word that will sit on a sunny shelf in my brain for awhile, instead of lurking in a recess, undefined and misunderstood.