Lexical Definition

‎σημειόω‎ sēmeióō (say-mi-o'-o) to note ^G:V
from ‎σημεῖον‎

note.

• to distinguish, i.e. mark (for avoidance)

Abbott-Smith

σημειόω, -ῶ (< σημεῖον), [in LXX: Ps 4:6* (נשׂא)* ;]
to mark, note. Mid., to note for oneself: II Th 3:14 (freq. in π.; v. ICC, M, Th., in l.).†

Abbott-Smith References

Liddell-Scott-Jones

σημειόω-όω

(Doric dialect σᾱμ- [Refs 1st c.BC+], mark (by milestones), [Refs 2nd c.BC+]; seal, ἐπιστολὰς -ωμένας σφραγῖδι [Refs 1st c.BC+]:—passive, to be marked or stamped, [Refs]

__2 give a signal, impersonal in passive, ὅταν σημειόωωθῇ Aen. Tact.22.23 (codex M).
__II middle, mark for oneself, note down, ὅτι.. [Refs 4th c.BC+] (signed) Δυμᾶς, [Refs 1st c.AD+]; take notice of, pay honour to.. , ὅπως ὁ δῆμος φαίνηται τοὺς καλοὺς κἀγαθοὺς τῶν ἀνδρῶν σημειόωούμενος [Refs]
__II.2 interpret anything as a sign or portent, [Refs 2nd c.BC+]; infer as from a sign, ὁ ἐκ τῆς ἐναργείας -ούμενος περὶ τῶν ἀδήλων [σημειόωώσεων” 15, compare 4th-3rd c.BC: Epicurus Philosophus “Epistulae” 2p.47U., 2nd c.AD: Sextus Empiricus Philosophus “adversus Mathematicos” 8.271 ">Refs 4th c.BC+]:—in Medicine texts, diagnose, [Refs 2nd c.AD+]; later, examine, σημειόωωσόμεθα κοπαρίῳ [Refs 7th c.AD+]
__II.3 in Grammars, of marginal marks, σημείωσαι,= nota bene, Hdn.Gr.[Refs]:—in passive, σημειόωοῦται δὲ ὅτι.. [Refs 8th c.BC+]; τὰ σεσημειόωωμένα noted as exceptions, [Refs 2nd c.AD+] H.: future σεσημειόωώσεται [Refs 2nd c.AD+]