In bank check ,we can see "pay to the order of".pay to the order of tom means that pay my money in the bank to tom,what does order mean here?

1. pay to is a whole part,the order of tom is a whole part.Or pay to the order of is a whole part?

2. order here means :

   a. command b. willing c. request d. rule

In bank check ,we can see "pay to the order of".pay to the order of tom means that pay my money in the bank to tom,what does order mean here?

1.pay to is a whole part,the order of tom is another whole part.Or pay to the order of is a whole part?

2.order here means :

 a. command , instruction
 b. willing
 c. request
 d. rule