What does "obsolete" refer to?

The term "obsolete" refers to something that is no longer in use or has fallen out of date. It describes items, ideas, or practices that have been replaced by newer alternatives or advancements, making them less relevant or completely irrelevant in contemporary usage. For instance, technologies such as floppy disks are often considered obsolete due to the emergence of more modern storage solutions. This understanding underscores why the concept of being "outdated" aligns perfectly with the definition of "obsolete."

The other choices present concepts that are contrary to the meaning of "obsolete." For instance, "newly created" indicates something that is fresh or recently developed, directly opposing the idea of being outdated. "Frequently used" suggests that an item or concept remains relevant and in active use, which contradicts the notion of obsolescence. Lastly, "essential" implies a necessity or critical importance, again contrasting with the idea of being outdated. All these factors highlight why the correct answer is indeed "outdated."