Intertwine (verb)

1. To cause to become intertwined or to become intertwined with something else.
2. To become intertwined with something else.

Origin:

From latin inter- + twine.

Examples:

1. The couple held hands as they walked, their fingers intertwining.
2. The branches of the trees were intertwining, making it difficult to pass through.
3. The story intertwines the lives of several different characters.
4. The two companies have decided to intertwine their operations.
5. The melody of the song intertwines several different themes.