Intel initially launched the Pentium series in 1993, while the Celeron series was launched in 1998. While the Celeron series was always aimed at the budget segment, the Pentium models were actually flagship-grade processors. At least until the launch of the modern Intel Core series, which replaced them as the top-of-the-line processors in 2006.
Since then, the Pentium line has been split into two variants. The Pentium Silver, which was used in low-power devices, and the Pentium Gold, which was meant for entry-level desktops. The Celeron processors remained at the bottom of the lineup, along with the Atom series. Now, both Pentium and Celeron brands have been dropped officially, with only the Atom, Core and Xeon series retaining their names.
From this point onwards, the chipsets that fall in these lineups with be simply called Intel Processors. This move was made in an effort to simplify Intel's offerings and make it easier for customers to select the right category for their use cases. This marks the end of almost 3 decades of Intel branding conventions, which made these sub-brands household names that everyone recognized instantly.
While the change has been announced officially, it will still take a few months before the names actually disappear from all the supported products and their marketing materials. It will be a sad day for nerds and computing enthusiasts who probably starting their computing journey with one of these processors.
