Cymek said:

Bubblecar said:

Mustard and custard do not share a direct or similar etymology.

Despite their similar spelling and yellow colour, they come from entirely different roots: mustard derives from Latin for “burning wine” (mustum ardens), while custard stems from French for “crust of a tart” (croustade).

You couldn’t really swap them for each other in cooking either

what’s that got to do with the priors of bustard in English then