An entry taken from Onomasticon Tacticon 26, but with a clear error (already noted in Stephanus’ Thesaurum s.v. ζυγός ) -- because the definition there relates to the verb στοιχεῖν , “to march in file”, which is a manoeuvre opposite to ζυγεῖν “to march in line”. In Onomasticon tacticon 25 we find the definition that should have been used instead of this one: “ζυγεῖν means to be placed in a straight line following the front line, and to be in parallel lines”.
Aelianus Tacticus, Tactica 7, writes: “we say ζυγειν to be in the same line, following the front line, with the men who are preceding or those who are at the rear, while we say στοιχειν to be in the same line, following the one which goes in depth, with the rear-guard leaders [ουραγοί ] and the company-commanders [λοξηογοί ]”; cf. beta 28.
These same concepts are to be found in a military writer earlier than Aelianus: Asclepiodotus, Tactica 2.5-2.6.
On the same matter see also delta 1257.
[1] In order to make sense, this additional clause does need the reading stoichos (from ms F). not a repetition of stichos.