Lexical Definition

‎πλάξ‎ pláx (plax) tablet ^G:N-F
from ‎πλάσσω‎

table.

• a moulding-board, i.e. flat surface ("plate", or tablet, literally or figuratively)

Abbott-Smith

πλάξ, -ακός, ἡ, [in LXX for לוּחַ;]
anything flat and broad.
1. a plain (poët.).
2. In late writers (Luc., al.), a flat stone, a tablet: II Co 3:3, He 9:4.†

Abbott-Smith References

Liddell-Scott-Jones

πλάξ, πλᾰκός, ἡ,

anything flat and broad, especially flat land, plain, πᾶσαν ἠπείρου πλάκα [Refs 4th c.BC+]; Φλεγραίαν π. [Refs]; νυχίαν π., of Psyttaleia (perhaps μυχίαν), [Refs 5th c.BC+]; νεκύων πλάκα [Refs 5th c.BC+]; also of sea and sky, πόντου πλάξ the ocean-plain, [Refs 6th c.BC+]; ποντία, πελαγία π., [Refs 5th c.BC+]; αἰθερία πλάξ [Refs 5th c.BC+]; flat top of a hill, table-land, Σουνίου, Οἴτης π., [Refs 5th c.BC+]; ἀπ᾽ ἄκρας πυργώδους πλακός from the flat top of the towering hill, [Refs 5th c.BC+]

__2 flat stone, tablet, ἐργώνας τᾶν πλακῶν τᾶς τομᾶς εἰς τὸν ὀχετόν [Refs 3rd c.BC+]; π. ἐπιγεγραμμέναι [Refs 1st c.AD+]; of the [LXX+NT+2nd c.AD+]; tombstone, [Refs]: plural, slabs of marble, Chor.p.89 [Refs 5th c.BC+]; ὥσπερ μαρμάρου π., of ice, [Refs 4th c.AD+]
__2.b πλάκες χρυσίου gold plates, [Refs 1st c.BC+]; ἡ ἐντὸς π. τῶν κογχυλίων the inner surface.., [Refs 4th c.BC+]
__2.c ἡ π. τοῦ βαλανίου τούτου probably part of the furnace, [Refs]. d. plural, flakes of ἀρσενικὸν τὸ πλακῶδες, [Refs 1st c.AD+]
__3 in plural, flaps, tail-fins of crustacea, [Refs 4th c.BC+]
__3.b folds within certain parts of the ruminant stomach, [Refs]
__4 κοπτῆς πλάκες,πλακοῦντες, [Refs 2nd c.AD+]. (Cf. Lett.plakt 'become flat'.)

_{LSJ Scripture Refs: LXX.Exod.31.18 ☩ Heb.9.4 ☩ 2Cor.3.3}