Is it possible to combine multiple purchase order of a vendor into single item receipt?

No

@Luis Thank you for your response. I have read somewhere that it is possible through inbound shipment. Do you have any idea about it?

Nope, it is still not possible. Yes you can create one Inbound Shipment against multiple PO, but later when you proceed the Inbound Shipment, IR will still be created per PO. If you don't use Landed Cost, then using Inbound Shipment is okay, but be careful when you have a Landed Cost, as the Landed Cost will be non-editable in the IR if you are creating it by Inbound Shipment

@Fakhri Hilmi Thank you for your detailed response.

@Alvi You can then have 1 Vendor Bill for multiple IRs

@AK47 Thank you for your response. Actually, the requirement is to combine multiple POs in single IR not bill at the moment.

@Alvi only way would be to combine the lines of the PO into one PO and then receive that. Otherwise...custom solution with custom records could be done as well.