Dencun includes simultaneous upgrades happening on the two sides of the blockchain. The “Cancun” upgrade will happen on the execution layer, where all protocol rules reside, while the consensus layer, which makes sure that blocks are validated, will go through its own fork known as “Deneb.” The name “Dencun” is a portmanteau of the names of the simultaneous upgrades.
Source: https://www.coindesk.com/tech/2023/06/08/ethereum-developers-cement-final-lineup-of-changes-in-dencun-upgrade/?utm_medium=referral&utm_source=rss&utm_campaign=headlines