A Google algorithm update refers to when Google updates or "tweaks" its algorithm to vary what the SERP displays. These updates enhance results and ensure that users are satisfied with the pages suggested.
As the leading search engine, Google must deliver the most relevant results possible to ensure that users are viewing the best content for their needs. It takes a variety of factors into account, such as user expectations and technology advancements.
As a business owner or marketer, it's important to stay on top of these updates and adjust your SEO strategy accordingly.