Wikipedia says Palworld's 1.0 update was expected to bring new mechanics, areas, and content.
The phrase describes the scope of Palworld's transition from early access to its full 1.0 release. “Content” is the broad category covering additions such as new creatures, story material, locations, missions, items, and other playable material; it is not a reference specifically to servers, cutscenes, or soundtracks.
Palworld began early access on January 19, 2024, with players exploring the Palpagos Islands, capturing Pals, building bases, crafting equipment, and fighting faction leaders. Pocketpair used subsequent updates to expand that foundation before the full release.
A common mix-up is treating “content” as another isolated feature alongside mechanics and areas. In the wording of the question, it is the umbrella term that completes the list. Mechanics describe how the game works, areas describe where players go, and content describes the broader additions populating those systems and spaces.