INKHORN (קֶ֫סֶת, H7879, קֶשֶׂת). The term is found in Ezekiel 9:2, 3, 11 in the KJV (RSV Writing case). An inkhorn consisted of a case for reed pens and some sort of container for ink near the upper end of the case. It was carried in the belt. Monuments of all periods show the Egyp. palette, a long narrow board with grooves for pens and circular hollows for ink.
International Standard Bible Encyclopedia (1915)
This term "inkhorn" occurs 3 times in Eze 9 (9:2,3,11), in the phrase "writer’s inkhorn upon his loins" (or "by his side"). The word is more exactly "implement case," or "writing-case" (calamarium atramentarium, theca calamaria, theca libraria, graphiaria). This may have been the Egyptian palette (Budge, Mummy, 350-52) seen so often in the monuments of all periods, or the later form of pen-case with ink-well attached, which is a modified form adapted for ink carried in fluid form. The Egyptian palette was carried characteristically over the shoulder or under the arm, neither of which methods is strictly "upon the loins." The manner of carrying, therefore, was doubtless in the girdle, as in modern oriental usage (Benzinger, Hebrew Archaeol., 185). A good example of the pen-case and inkwell writing-case (given also in Garucci, Daremberg-Saglio, Gardthausen, etc.) is given from the original in Birt, Die Buchrolle in der Kunst, 220, and is reproduced (a) in this article, together with (b) an Egyptian palette. Whether the form of Ezekiel’s case approached the palette or the ink-well type probably depends on the question of whether dry ink or fluid ink was used in Ezekiel’s time (see Ink). Compare Hieronymus at the place, and for literature, see Writing, and especially Gardthausen, Greek Palestine, 1911, I, 193-94.