Floor Price
Floor price is the lowest asking price for any NFT in a collection at a given moment — the cheapest listed item, and therefore the minimum cost of owning any piece from that collection. It is the most quoted single number for NFT collections, used roughly the way a share price is used for stocks.
For example, if a 10,000-item collection has its cheapest active listing at 0.8 ETH, the floor price is 0.8 ETH, even though rare items in the same collection may be listed for far more. Marketplaces display the floor prominently, and traders talk about collections "holding their floor" or the floor "bleeding" downward.
A common misconception is that the floor price tells you what you could sell for; it is an asking price, not a sale price, and in a thin market the actual bids may sit well below the cheapest listing. Floor prices are also manipulable: a few coordinated listings or delistings can move the number without any real sales. Multiplying floor price by collection size to get a "market cap" overstates value for the same reason — most items could not actually be sold at the floor at once. Treat it as a quick snapshot of sentiment, not a reliable valuation.