Mother sauces are a French thing. They're béchamel, velouté, espagnole, tomate, and mayonnaise.

Some stuff can be made shorter by just saying things like "deglaze the pan" instead of "pour some flavorful liquid such as stock, broth, or wine in this hot pan that you think would compliment the taste of whatever you're cooking and make sure to scrape the brown bits while at it." It's the same thing as programming, one might say to a professional programmer to "sum these items" while a beginning programmer would get "write a for loop with an accumulator variable, and for each iteration of the loop add the item to your accumulator."

They're both the same thing, it's just that one is more succinct.