διάκενον
From LSJ
Ἀναξαγόρας δύο ἔλεγε διδασκαλίας εἶναι θανάτου, τόν τε πρὸ τοῦ γενέσθαι χρόνον καὶ τὸν ὕπνον → Anaxagoras used to say that we have two teachers for death: the time before we were born and sleep | Anaxagoras said that there are two rehearsals for death: the time before being born and sleep
Russian (Dvoretsky)
διάκενον: τό пустой промежуток, интервал Thuc.: τὰ διάκενα Plat., Arst. пустоты, полости; τὰ διάκενα τῶν νόμων Plat. пробелы в законах; δ. δεδορκέναι Luc. (о скелете) глядеть пустыми глазницами.
Lexicon Thucydideum
vacuum spatium, intervallum, empty space, interval, 4.135.1, 5.71.3. 5.72.3.