Fish-eaters, a name given to a people, or rather to several different people, who lived wholly on fishes; the word is Greek, compounded of ἰχθύς, ἰχθύος, "fish," and ἐδέρειν, ἐδέρειν, "to eat."

The Ichthyophagi spoken by Ptolemy are placed by Sanfon in the provinces of Nanquia and Xantong. Agatharcides calls all the inhabitants between Carmania and Gedrosia by the name Ichthyophagi.

From the accounts given us of the Ichthyophagi by Herodotus, Strabo, Solinus, Plutarch, &c., it appears indeed that they had cattle, but that they made no use of them, excepting to feed their fish withal. They made their houses of large fish-bones, the ribs of whales serving them for their beams. The jaws of these animals served them for doors; and the mortars wherein they pounded their fish, and baked it at the sun, were nothing else but their vertebrae.

Ichthyoperia, an old term in Natural History, which is applied by Dr Hill to the bony palates and mouths of fishes, usually met with either fossil, in single pieces, or in fragments. They are of the same substance with the butonite; and are of very various figures, some broad and short, others longer and slender; some very gibbose, and others plainly arched. They are likewise of various sizes, from the tenth of an inch to two inches in length, and an inch in breadth.

Ickennild-street, is that old Roman highway, denominated from the Icenians, which extended from Yarmouth in Norfolk, the east part of the kingdom of the Iceni, to Barley in Hertfordshire, giving name in the way to several villages, as Ickworth, Icklingham, and Ickleton in that kingdom. From Barley to Royton it divides the counties of Cambridge and Hertford. From Ickleford it runs by Tring, crosses Bucks and Oxfordshire, passes the Thames at Goring, and extends to the west part of England.