"Spot" simply means the actual item, not a future, or option, or other derivative.
It's that simple.
("market" price is completely meaningless, all prices are market prices. It's simply a descriptive term, like saying "the current price" or "the usual price". One sense in which "market" price is used is simply the, so to speak, "raw" price without commissions or fees. Another way it is used is nothing more than the "going, current, typical" price. "market" price has no connection, at all, to whether or not the instrument is spot, a derivative, or whatever. It's just a descriptive term, like "good" or "fast sale" or "today's" or "going". For example, "I sold my house for a good price", "I got better than the market price for my house", "today's price of oil futures is high", "the going rate for mortgages is 3%", "the market price for corn is X, but I sure hope we can get a bit more than that for our truckload at the Farmer's Market today", "when we sold our house we unfortunately had to sell it very quickly so we got much less than the market rate", "it's great to buy a house from a divorcing couple as you can usually get it at less than the market rate" ... etc etc.)