What does OVNO mean?

OVNO stands for Or Very Near Offer. It's shorthand used in classified ads to say the seller will consider offers, but only ones close to the asking price rather than a low-ball offer.

What it means in practice: there's a bit of room to negotiate, but not much. It signals the price is close to what the seller actually expects to get, rather than being set high to leave lots of room for haggling.