Behind these arches are two rows of trefoil niches; and between them also rises a square column, of the Doric order, surmounted by carved pinnacles.

The simple trefoil aperture seems a fair architectural version of the clover-leaves.

Each jamb of the outside arch has four external and two internal attached shafts; the pointed arch is deeply moulded, while the arch rising from the fourth shaft is of round-headed trefoil form.

Separated from it by a very absurd and useless ditch, a Green Shamrock spread its trefoil leafage to the sun, and grew greener every day.

SHAMROCK, a small trefoil plant, the national emblem of Ireland; it is matter of dispute whether it is the wood-sorrel, a species of clover, or some other allied trefoil; the lesser yellow trefoil is perhaps the most commonly accepted symbol.