Strong’s Greek
G5069 — tetradion
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
τετράδιον
tetradion — pronounced tet-rad'-ee-on
neuter of a presumed derivative of tetras (a tetrad; from 5064); a quaternion or squad (picket) of four Roman soldiers:--quaternion. see GREEK for 5064
1 occurrence in the KJV.
Acts 12:4
And when he had apprehended him, he put him in prison, and delivered him to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people.