Lexical Definition

‎πέριξ‎ périx (per'-ix) around ^G:ADV
adverb from ‎περί‎

round about.

• all around, i.e. (as an adjective) circumjacent

Abbott-Smith

** πέριξ, adv., [in Al.: Le 13:33*;]
round about: αἱ π. πολεῖς, Ac 5:16.†

Abbott-Smith References

Liddell-Scott-Jones

πέριξ,

strengthened for περί, mostly Ionic dialect Prose and Trag. (in latter usually adverb):

__I preposition, round about, all round, with genitive, [Refs 5th c.BC+]
__I.2 rarely with dative, [Refs 5th c.BC+]
__I.3 commonly with accusative, [Refs 5th c.BC+]: mostly before its case, but also after,[Refs 5th c.BC+]
__II adverb round about, π. ὑπορύσσοντες τὸ τεῖχος [Refs 5th c.BC+]; κύκλῳ π. [Refs 5th c.BC+] circuitously, [Refs 5th c.BC+]: rare in Attic dialect Prose, π. πολιορκεῖν [Refs 5th c.BC+]; ὁ π. τόπος, οἱ π., [Refs 5th c.BC+]; ὁ π. χρόνος, i.e. all times save the present, [NT+4th c.BC+]

_{LSJ Scripture Refs: Acts.5.16}