ἐχυρότης
From LSJ
ὕπνος δεινὸν ἀνθρώποις κακόν → sleep is a terrible evil for humans (Menander, Sententiae monostichoi 1.523)
English (LSJ)
ητος, ἡ,
A strength, ἐν οἰκοδομίαις Ph.2.116, cf. 120, 1.478 (ἐχ- Pap.), 688, J.AJ15.11.4. (ὀχυρότης is a v.l. and shd. be preferred in Plb.1.57.6, but for καὶ ὀχ- (v.l. καὶ ἰσχ-) in Ph.1.644 καὶ ἐχ- shd. be restored.)
German (Pape)
[Seite 1127] ητος, ἡ, Haltbarkeit, Festigkeit, Philo.