Outdoor furniture has been retailing higher and higher over the last several years. Unless you're buying it from Target, K mart or Home Depot, you can expect to pay several hundred dollars for an ottoman, or several thousand dollars for an outdoor sofa.

What accounts for all those zeros, exactly? Something in the DNA.

Design. Step outside the big box, and furniture gets more sophisticated. Step outside the house, and it gets even more sophisticated.

For practical reasons, outdoor furnishings forgo the fabrics, embellishments and textures that adorn interior furniture. What's left behind is form, which means lines, shapes and silhouettes must be impeccable. European furniture companies known for their exquisite design, such as B&B Italia, have recently jumped on the outdoor bandwagon, raising the level of competition - and the prices.

Though patio furniture isn't typically the most comfortable seat in the house, some brands are attempting to buck that standard. This, too, costs money, as manufacturers invent ways to pump up the "cush" factor without the benefit of interior materials such as foams and padding.

In one of the more innovative, practical design applications of recent years, Canadian manufacturer Nuevo created two five-piece patio sets that can be stacked into a single, compact arrangement.

In the case of its Hourglass collection, the arrangement is a single column. In the case of the Capsule, it's an egg (or capsule) shape. When pool-party season is over, simply place the pieces together, like a 3-D puzzle, and stow in a corner of the garage.

Name. Pair a famous face with any product, and the appeal increases. Sometimes, as in the case of fashion designer Cynthia Rowley's Whim, a new line of outdoor furniture and accessories for Target, the appeal translates to more customers. On the higher end, it translates to steeper prices.

French interior designer Jacques Garcia teamed with furniture manufacturer McGuire to launch his first outdoor collection. Garcia saw the collaboration as a natural chance to borrow from the primitive shapes and textures of nature. The collection's 17 pieces are characterized by metal rivets, stone slabs and woven resin.

"These materials were new to me," Garcia says. "They forced me to go to the root of the shape itself, as it was envisioned at the origin."

Other names stepping out this season: rebel furniture designer Daniel Michalik, who handcrafted a collection of stools completely from reclaimed cork bottle stoppers; Joe Ruggiero's "Domino" wicker collection, and Belgian designer Bram Bollen, whose Vintage collection for Henry Hall Designs is made of molded plastic. Bollen's Vintage Chaise Lounge and Stacking Chairs are visual replicas of the curved plywood chairs of the 1950s.

Airloom quality. Airloom (noun): A piece made to withstand the elements as well as the passing years.

Outdoor finishes must be chip- and rust-resistant. Weaves must stand up to water from the sky and wet bathing suits. Fabrics must be tough enough to withstand dormant months in moldy basements and dirty garages. Special, and more costly, materials are the only answer.

Sunbrella has spent 45 years perfecting its furniture fabrics, constantly tweaking patented technologies to keep cushions long-lasting, fade-resistant and water-repellent.

Barlow Tyrie, a British-based manufacturer of outdoor furnishings, uses marine-grade steel instead of regular steel (for its resistance to oxidation), powder-coated aluminum instead of regular aluminum (also for anti-oxidation), and Textilene instead of regular upholstery fabric (for its flame-retardance, mildew resistance and low maintenance).

This spring, Alabama-based outdoor-furniture-maker Summer Classics rolled out N-Dura Resin, a recyclable, UV-resistant wicker weave meant to be long-lasting and gentler on the environment.

Aside from being armored against the wind and rain, a good chaise also will withstand the test of time. The potential for being able to refer to a piece of furniture as "my mother's" undoubtedly holds a certain monetary value. Many companies recognize this appeal by using the word heirloom in their marketing.

Heirloom also can signify history - that a piece has a story to tell. Retailer New York First is encountering much success with its new Bryant Park Table and Chairs, reproductions of those dotting New York's Bryant Park (selected by urban planner William Hollingsworth Whyte in the 1980s).

Though similar bistro-style patio furniture can be found for about $100, the Bryant Park set already has sold out at a retail price of more than $300. (Stock will be replenished in mid-June, the company says.)