τετράδιον

τό
A. guard of soldiers (normally consisting of four men), Ph. 2.533, Act.Ap. 12.4.
II. quaternion of parchment, POxy. 2156.10 (iv/v A.D.), Tz. H. 9.290; cf. τετράδειον.
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
An open-access project