The freshness factor is an element of search algorithms that gives greater weight to newer content over older content for some search queries. Search engines introduced the freshness factor for searches related to trending topics, recurring events (sports scores, awards and so on) and breaking news. The freshness factor prevents old, highly ranked pages from appearing first when new content is more appropriate to the query.
The freshness factor may also be called the Google freshness factor.
Techopedia explains Freshness Factor
Like all elements of search engine algorithms, most of what is known about the freshness factor has been pieced together by SEO experts. The freshness factor is believed to affect only searches where the timeliness of information is important. To effectively measure content freshness, search engines need to track a Web page when it first appears, noting updates and significant changes that can refresh older content to make it relevant again.