once
From LSJ
Ὁ μὲν βίος βραχύς, ἡ δὲ τέχνη μακρή, ὁ δὲ καιρὸς ὀξύς, ἡ δὲ πεῖρα σφαλερή, ἡ δὲ κρίσις χαλεπή → Life is short, art long, opportunity fleeting, experience misleading and judgment difficult
Ὁ μὲν βίος βραχύς, ἡ δὲ τέχνη μακρή, ὁ δὲ καιρὸς ὀξύς, ἡ δὲ πεῖρα σφαλερή, ἡ δὲ κρίσις χαλεπή → Life is short, art long, opportunity fleeting, experience misleading and judgment difficult
once for all: P. and V. εἰσάπαξ, P. καθάπαξ.
once upon a time: P. and V. ποτέ, ἤδη πότε, πάλαι ποτέ, V. ποτ' ἤδη; see formerly.
at once: see immediately.
together, alike: P. and V. ἅμα, ὁμοῦ, ὁμοίως, V. ὁμῶς.
