... or conversely, de-imply crown from tiara.

This is an alias/implication chain that does not work.

post #1480174

She is wearing a diadem, which because of the above chain is aliased to tiara, thus implying crown.

While this could perhaps be considered a tiara, methinks you would all agree this does not appear as a 'crown'.

(or is this just splitting hairs, and it is close enough that nobody cares?)

I would think that the thing she's wearing most resembles a circlet, not a diadem.

Like Clawdragons said, that's a circlet.