Suppose I am manuf. Pen. So the Business Process of Pen is 
from Purchase of Plastic material,led,nib,cap,making die 
for manuf.pen,paste some sticker,vendor 
payment,Delivery,Discount,Term of payment,Who is 
customer,consumersetting dealer,distributor,Sales 
order,Delivery,Billing,Receiving payment.

So Complete flow of business from starting to end that is 
called business process

Business process is a collection of related, structured 
activities--a chain of events--that produce a specific 
service or product for a particular customer or customers.
A business process is a recipe for achieving a commercial 
result. Each business process has inputs, method and 
outputs. The inputs are a pre-requisite that must be in 
place before the method can be put into practice. When the 
method is applied to the inputs then certain outputs will 
be created.