Definition of yet :
1. Any one of several species of large marine gastropods belonging to the genus Yetus, or Cymba; a boat shell.
2. At the same time; by continuance from a former state; still.
3. Before some future time; before the end; eventually; in time.
4. Even; - used emphatically.
5. In addition; further; besides; over and above; still.
6. Nevertheless; notwithstanding; however.
7. Up to the present time; thus far; hitherto; until now; - and with the negative, not yet, not up to the present time; not as soon as now; as, Is it time to go? Not yet. See As yet, under As, conj.
to that extent, insofar, additionally, sooner or later, item, further, until, all the same, merely, barely, hitherto, up to now, until now, more, still and all, and, previously, save, to that degree, before, earlier, despite, withal, in so far, affirm, stock-still, too, sense, tho, increase, likewise, even, precede, also, to date, so far, only, big, as yet, thus far, that, except, heretofore, til now, besides, eventually, nonetheless, one of these days, just, soon enough, in time, even so, unless, notwithstanding, provided
however (part of speech: adverb)
while (part of speech: adverb)