Definitions of tie up:

• verb:   invest so as to make unavailable for other purposes
• verb:   finish the last row
• verb:   restrain from moving or operating normally
• verb:   secure with or as if with ropes

  Example: "Tie up the old newspapes and bring them to the recycling shed"

• verb:   secure in or as if in a berth or dock

  Example: "Tie up the boat"