Resale is selling something you already bought, rather than making it yourself or selling it brand-new from the factory. A shop that buys clothes and sells them on is in the resale business; a concert ticket marked "no resale" means you must not sell your seat to someone else. In housing, a resale flat is one that has had an owner before — not a new one from the builder. The matching verb is resell. People also say "second-hand" or "used" for the goods themselves; resale names the selling-on. Though actually, "for resale" on a box in a warehouse just means the stock is meant to be sold again by a shop, not kept by the first buyer.