~도록 (do-rok) –
1. to the extent/degree of
2. in order to/so as to
1. For the first meaning “to the extent/degree of”, you can think of it as “so much so” or “until the point”, basically to emphasise or even exaggerate how much/many someone did something.
Example: 그 친구는 항상 배터지도록 먹어서 살이 많이 쪘어.
That friend always eat to the extent of his stomach bursting so he put on a lot of weight.
2. The second meaning “in order to/so as to” is quite similar to the particle (으)로 in that it is to express the means of doing something.
The main difference is you would use ~도록 when expressing an action therefore attaching it to a verb, whereas (으)로 is almost always attached to a noun.
Example: 살이 많이 빠지도록 식사 할 때마다 그냥 충분히 먹으면 더 좋아.
In order to lose a lot of weight, just eat sufficiently for every meal would be better.
3. The third and last meaning or rather usage of ~도록 is to request or command someone to do something.
Example: 넌 살이 많이 쪄서 그냥 적게 먹도록 하라.
You put on a lot of weight so just eat lesser.