A breakout board “breaks out” the pins of an integrated circuit onto a printed circuit board that has its own pins usually in a way so that they are spaced perfectly for a solderless breadboard, giving you easy access to use the said integrated circuit.
here the IC is the MCU and a few other components.
A Uno or MEGA would no match the easy access for a solderless breadboard but other boards such as the Nano or some ESP32 etc do match the description
so yes you probably could say so even if it's not the usual way of seing this