المعنى الاصطلاحي

A collision of two bodies, such as two horsemen, two boats, etc., impacting each other by their weight and power.

الشرح المختصر

"Istidām" (collision): If two free persons who are competent for religious duty collide intentionally, in such as a way that it is likely to cause death, then the blood money of the killed person is due on the other person. If one of them only collided into the other, then the indemnity is on the one who caused the "istidām". If both are riding or one is riding and the other walking, then the damage done to both riding mounts or either of them is to be compensated for by the other. If an "istidām" is caused by force majeure, such as strong winds or storms, then no one is responsible for anything. If an "istidām" is due to the carelessness of either party, this party is responsible for indemnity.

التعريف اللغوي المختصر

"Istidām": collision of two solid objects, with each hitting the other with its weight.