heos (Greek #2193)
a conjunction, preposition and adverb of continuance, until (of time and place)
KJV usage: even (until, unto), (as) far (as), how long, (un-)til(-l), (hither-, un-, up) to, while(-s).
Pronounce: heh'-oce
Origin: of uncertain affinity
hotou (Greek #3755)
during which same time, i.e. whilst
KJV usage: whiles.
Pronounce: hot'-oo
Origin: for the genitive case of 3748 (as adverb)