"By the name of; called."

This is a word that beckons to be written again and again because of its appearance, which is mystical somehow. Interesting pet name: A cat yclept 'Yclept'. Try saying that out loud--great fun, if you're looking for a diversion.

Edit: Oh, and I wanted to add Quinion's note about the 'y' because it was interesting:

"The initial y was once the standard way of marking the past participle: yclensed, yfastened, ypunched, and dozens of others. It was the Old English equivalent of a form which still exists, for example, as ge– in modern German. Advice to budding writers: best avoided!"