Definitions:

1. in a manner that facilitates adverb
   • I observed the snakes so I could describe their behavior.
2. in such a condition or manner, especially as expressed or implied adverb
   • They're happy and I hope they will remain so
3. in the way indicated adverb
   • hold the brush so
4. to a certain unspecified extent or degree adverb
   • I can only go so far with this student
5. to a very great extent or degree adverb
   • the idea is so obvious
6. to an extent or degree as expressed adverb
   • I was so tired I could hardly stand.

Synonyms:

• and so
• and then
• hence
• indeed
• soh
• sol
• then
• thence
• therefore
• thus
• thusly