What does an HOA actually own?

The association holds title, not the owners

If you sit on the board of a subdivision HOA, the common area, entrance signage, retention pond, private streets, clubhouse, is not something you and your neighbors own together. The association, as its own legal entity, holds title to it directly.

"The typical subdivision has a common area that's owned by the HOA by virtue of a recorded deed or plat."

Source: Common area ownership in condominiums and subdivisions, State Bar of Texas

Condominiums work differently. There, the unit owners own the common area together, as tenants in common, in undivided shares. A board member who transfers into an HOA from condo experience often carries that assumption over, and it is wrong. Your community's actual legal category, most likely a planned community, was set the day its declaration was recorded.

Exactly what the association was deeded, and how much of it, is a question only your own recorded declaration and plat can answer. Read them before assuming.

Common elements, and the parts carved out for one owner

Everything in the community that is not a separately owned unit or lot is a common element.

"all portions of the common-interest community other than the units, including easements in favor of units or the common elements over other units."

Source: Nevada Revised Statutes Chapter 116, NRS 116.017, Nevada Legislature

Some common property is set aside for just one or a few owners, a balcony, an assigned parking space, a patio attached to a single unit. Statutes call this a limited common element: property allocated "for the exclusive use of one or more but fewer than all of the units" (NRS 116.059, Nevada Legislature). It is still common property, legally, even though only certain owners may use it.

Owning it and maintaining it are two different questions

Who holds title does not automatically answer who fixes what. Unless the declaration says otherwise, the default rule splits the work along the same line as the title.

"the association has the duty to provide for the maintenance, repair and replacement of the common elements, and each unit's owner has the duty to provide for the maintenance, repair and replacement of his or her unit."

Source: Nevada Revised Statutes Chapter 116, NRS 116.3107, Nevada Legislature

That is a default, not a fixed line. Declarations frequently reassign specific items, windows, exterior doors, an HVAC condenser sitting outside a unit, differently. A board that assumes the default applies without reading its own declaration can be wrong about who is actually on the hook for a repair. The full mechanics of that line live in association responsibility versus owner responsibility.