What is an executive order by a US president?
An executive order is a directive signed by the US president which can have the same effect as laws passed by the US Congress but which need only the president's signature to become effective. They are therefore attractive to presidents who want to achieve things quickly. The president's powers to issue executive orders stems from article II of the US constitution which gives executive powers and makes him the commander in chief. Executive orders can be overruled by a law of Congress, but there is presidential veto.
Does the attack when a man drove a bus into worshippers at Finsbury Park mosque count as terrorism?