Steve Barnes' World of Happiness

"Cockle."

The Oxford dictionary:

1. an edible burrowing bivalve mollusc with a strong ribbed shell.

Why, yes. The definition includes "edible."

I haven't searched every related definition, but I checked the definitions of "human," "ape," and "mammal," and – counter-intuitively, perhaps – found "edible" in none of them.

A puzzle?

(Note: I use it routinely regardless, but in this case, I used the "Oxford comma" slightly more consciously.)

(Note: I've observed the BBC phrases some headlines as questions, perhaps to keep them journalistic, according to their estimation.)