Verb (1-dan, intransitive)
1. to open out (of a view, scenery, etc.); to spread out; to become clear (of a road, visibility, etc.); to open up
視界が開けたとき、俺はぽかんとそれを見ていた。When the view opened up, I just stared at it blankly.
2. to improve (of luck, prospects, etc.); to get better
3. to develop (of a town, civilization, etc.); to become civilized; to modernize; to grow; to advance (of knowledge, ideas, etc.)
4. to be sensible; to be understanding; to be enlightened
5. to open (of a new road, railway, etc.); to be opened to traffic
6. to become populous; to become densely built; to become bustling