what's the meaning of product_vendor_id?

I can't understand the meaning of the product_vendor_id field...
Could you explain?

Hello,

The field "product_vendor_id" is not used by HikaShop but Nicolas added it a long time ago because he though that it could be useful.
Today, that field is still not used by HikaShop but it is used by HikaMarket.

Regards,

and what is the meaning for Hikamarket?

Hi,

It's that field which makes the link between the products in HikaShop and the vendors in HikaMarket. So in there, you'll find the id of a vendor from the vendors of HikaMarket.
When a product is attached to a vendor, the sales of that product will be linked to the vendor's account and you can setup commissions and fees on these sales. If you allow it in HikaMarket, vendors can also manage their products on the frontend.