The Collaborative International Dictionary
Phrygian cap \Phryg"i*an cap`\ A close-fitting cap represented in Greek art as worn by Orientals, assumed to have been conical in shape. It has been adopted in modern art as the so-called liberty cap, or cap of liberty.
Wikipedia
The Phrygian cap is a soft conical cap with the top pulled forward, associated in antiquity with several peoples in Eastern Europe and Anatolia, including Phrygia, Dacia and the Balkans. In early modern Europe it came to signify freedom and the pursuit of liberty through a confusion with the pileus, the felt cap of manumitted (emancipated) slaves of ancient Rome. Accordingly, the Phrygian cap is sometimes called a liberty cap; in artistic representations it signifies freedom and the pursuit of liberty.
In medicine, a Phrygian cap is the folded portion of some gallbladders that resembles the Phrygian cap (a soft conical cap with the top pulled forward, associated in antiquity with the inhabitants of Phrygia, a region of central Anatolia). It is a normal anatomical variant seen in 1-6% of patients. It is caused by a fold in the gallbladder where the gallbladder fundus joins the gallbladder body. Apart from the chance of being mistaken for stones on a sonogram, it has no other medical implications nor does it predispose one to other diseases.
edited-copy.jpg|CT scan showing a phrygian cap
Usage examples of "phrygian cap".
Midas was able to hide these ears under his Phrygian cap and his disgrace was known only to his barber.
He had stood nervously shifting his red Phrygian cap from one hand to another, while his eye roved restlessly over the crowded court.
The flickering tallow candle behind him threw into bold silhouette his square, massive head, crowned with its Phrygian cap, and the great breadth of his shoulders, with the shabby knitted spencer and low, turned-down collar.
But Marcus proudly wore his Phrygian cap, pointed forward at the front, which marked him out as an adherent of the cult of Cybele, old-fashioned but popular locally.
He was a big, doleful man, a bronze worker, with big hands scarred by splashes of liquid metal, and he wore a Phrygian cap, just as her father had done.
Hellenistic sculpture has popularised the scene of the immolation of a bull by Mithra, wearing a Phrygian cap, in one of those grottoes where the initiates gathered.
He was a fine-looking fellow, with a spick-span new red Phrygian cap.