Is that like "commingling"? What is "commingling"?

Commingling is like transmutation, in that by commingling funds you could transmute them into marital funds. Our example of depositing your paycheck into the account with the separate inheritance is an example of commingling. By mixing the marital property (your paycheck) with the separate property (your inheritance), you have "commingled" them, and they cannot be considered separate property anymore.

An example often used is the one of making an omelet: if you crack an egg into a bowl, the white and the yolk are distinct and can be separated, perhaps with some difficulty. But if you mix the white and the yolk together, they cannot be separated, and now the egg mixture is mostly yellow. So, the white is your inheritance, the yolk is your paycheck. By depositing the paycheck into the same inheritance account, you have mixed the egg. It is now yellow; that is, it has taken on the characteristics of the marital property.