What is difference between sight draft and bill of exchange

Draft is the name used in trade finace for bill of exchange normally for LC documents.Hence there is no difference between draft and bill of exchange

A sight draft means the amount under LC is payable immidietly upon submission of the douments for negotiation under the LC. The amount is normally paid with three days from receipt of documents at the LC issuing bank and if all the documents are in order as per the LC terms