What is a…
mixed multitude

Exodus 12:38 KJV

This is a foreign multitude of people, a class who accompanied the Israelites as they journeyed from Rameses to Succoth, the first stage of their Exodus from Egyptian slavery.

These were probably miscellaneous hangers-on to the Hebrews, whether Egyptians of the lower orders, or the remains of the Hyksos as some think.

The same thing happened on the return of the Jews from Babylon (Neh. 13:3), a “mixed multitude” accompanied them so far.