Meshtastic is the hardware that provides an open source RF cloud. Reticulum is the private and encrypted transport protocol. When combined, it will cause a lot of butthurt for people with central planning aspirations.
Discussion
No, Meshtastic isn't the hardware.
Both these things are more or less at the same level within the stack, but have different goals, and Reticulum will work on the same kind of low power LoRa hardware as Meshtastic, but Reticulum can also can use other network bearers like WIFI, Ethernet, etc.
Here's an interesting brief write up (not mine) that does a comparison.
https://blog.erethon.com/blog/2024/01/31/comparing-reticulum-and-meshtastic/