Usage: 3 forms in 5 verses
Form Translated As     In Verse(s)
πύξια writing-tablets LXX.Exod.24.12
πυξίου a writing-tablet LXX.Isa.30.8
πυξίον a writing tablet LXX.2Kgs.21.13
a writing-tablet LXX.Song.5.14LXX.Hab.2.2

Liddell-Scott-Jones

πυξίον (puxion) a writing tablet G:N-N

πυξίον-ίον, τό,

tablet of box-wood for painting on, [Refs 4th c.BC+]; for writing on, [Refs 5th c.BC+]

__II list, hence section, division, τῷ ὀγδόῳ π. τῆς γερουσίας [Refs]