The Hebrew word so rendered means simply a round vessel or cup for containing ink, which was generally worn by writers in the girdle ( Ezekiel 9:2 Ezekiel 9:3 Ezekiel 9:11 ). The word "inkhorn" was used by the translators, because in former times in this country horns were used for containing ink.
M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition,
published by Thomas Nelson, 1897. Public Domain, copy freely.
[N] indicates this entry was also found in Nave's Topical Bible
Bibliography InformationEaston, Matthew George. "Entry for Inkhorn". "Easton's Bible Dictionary".