We’ve sorted out what semolina is. So we know the semolina pilchard of which John Lennon sang in “I Am the Walrus” was not a girl (contrary to my youthful first impression). But I didn’t go into what a pilchard is.
I’m inclined to think it might be the sort of thing one filches. Who would filch it? Not a milch-cow – they prefer mulch. Perhaps a crabalocker fishwife. Who found it in a gulch. But if she eats it, will she belch? Or squelch it? (I’ll tell you this: whatever it is, lch notwithstanding, it doesn’t involve alchemy in a sepulchre. That would just sound wrong.)
So it’s an edible. No, it’s not chard that comes in a pill. Actually, it’s a sardine. You can buy these in cans and feed them to cats (or to yourself). Do pilchard and sardine mean the same thing? Depends on whom you ask. Some use sardine to mean ‘young pilchard’. Others divide them by species. Whatever, there’s a lot of overlap.
This word used to be pilcher or pylcher, and ended up with an ard ending by analogy with wizard, buzzard, laggard, etc. It was not pilcher because it wears a pilch (an outer garment made of animal skin, with the fur on the inside) – ew, it sure doesn’t – or a pilcher (in Oz and NZ, a flannel overcloth for diapers) – double ew – or because it is related to romance novelist Rosamunde Pilcher (a genetic connection has not been proven). No, etymologists have ruled out the red herrings. Unfortunately, what they have left to go on is… zilch. Hmm. Fishy.