5 terms to look for instead of 'penthouse' if you're on the hunt for a luxury apartment with a unique layout, high ceilings, or outdoor space

1. Condo townhouse

"Generally these are condominiums that are just as much like a single family home," Lavrenov said. "They mix an apartment and townhouse together."

A four-bedroom home on Manhattan's Upper East Side listed by Corcoran for $4.95 million includes a private entrance like a townhouse would, in addition to condo-like amenities such as a doorman and fitness facility that comes with a Peloton bike.

Condo townhouses are also called "maisonettes," and in Lavrenov's view, the two terms are interchangeable.

2. Maisonette

"Maisonette" is the marketing term more often used these days for a condo townhouse, according to Lavrenov, typically referring to a unit on two stories of a larger building that has its own private entrance.

The Wall Street Journal previously noted maisonettes were being rebranded into "coveted real estate" and described them as "townhouse-like spaces with building services."

In Manhattan, for instance, a six-bedroom, two-level co-op near Central Park for sale for $7.7 million is being marketed as a "maisonette" and includes amenities such as a private entrance, a 24-hour doorman, a live-in resident manager, gym, bike room, laundry, and storage, according to the listing.

Real estate database StreetEasy says the private entrances maisonettes typically offer are ideal for "celebrities or recluses" because of the "easy and anonymous in-and-out access," Laura Vecsey wrote.

3. Garden apartment

Instead of looking at the very top of a building for luxury, you might want to look at the very bottom.

"A lot of time ground floor apartments can be really unique," Lavrenov said. " ... Sometimes you'll see certain listings and certain condos will be marketing their first floors as 'Garden A' or 'Garden B.' That usually means that there's some sort of outdoor space attached to the property, there's a patio of some sort."

Often these properties go underground, making them duplexes.

"So sometimes there you get a really unique layout," Lavrenov said.

4. Duplex or triplex

An apartment listed as a duplex or a triplex — essentially "anything that combines apartments," can be very attractive, according to Lavrenov.

"Let's say you had an apartment combination of floors 15 through 18 and the penthouse is on 19," he said. "That apartment can be just as attractive as the penthouse and probably even more unique."

Lavrenov pointed to a building he's handled sales for called The Edge, where a 1,800-square-foot penthouse at the top had a duplex layout, "decent" views, and high ceilings. But there was a comparable — and some would say better — option below.

"Interestingly enough, there was an apartment just like that on the seventh floor with a much bigger terrace, same kinds of ceilings, a more unique floor plan, more square footage," Lavrenov said. "... It was just over 2,000 square feet. It was a fantastic duplex, had 20-foot ceilings, 20-foot windows. So that certainly shows the value, that it's along the likeness of what a penthouse would be."

5. Sky loft

Some real estate agents bet that catchy terms such as "sky loft" will attract buyers more than a traditional "penthouse" moniker.

"I have a listing at 234 E. 23rd Street where it is the first setback in the building and theoretically a penthouse, but we decided to market it as a 'sky loft,' you know, something to differentiate it," Steve Gold, a luxury real estate agent at Corcoran and star of Bravo's "Million Dollar Listing New York."

Similar to a penthouse, the five-bedroom apartment includes two large terraces, floor-to-ceiling windows, and "panoramic 360-degree views," according to the listing, features that would prompt some real estate brokers to call it a penthouse even though it's not on the top floor.

It was previously rented for nearly $50,000 per month and is now for sale for $10.9 million.