They connect tissue to bone (7)
I believe the answer is:
tendons
'they connect tissue to bone' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tendons that I've seen before include "Tissues connecting muscles to bones" , "They connect tissue to bone" , "they're able to articulate" , "Cords of tissue connecting muscle to bone" , "Tissues connecting muscle to bone" .)