אָכֵן

From LSJ

Τοὺς τῆς φύσεως οὐκ ἔστι λανθάνειν (μανθάνειν) νόμους → Legibus naturae non potest evadier → Naturgesetze keiner insgeheim verletzt

Menander, Monostichoi, 492

English (Strong)

from כּוּן (compare כֵּן); firmly; figuratively, surely; also (advers.) but: but, certainly, nevertheless, surely, truly, verily.