Most international cookbooks on Vietnamese cooking call this sauce
nước chấm, but that’s too generic;
nước chấm simply means “sauce for dipping,” and doesn’t specify if the sauce is made with soy, mayonnaise, fish, or any other base. I call this
nước mắm pha nhạt (“mild-flavored fish sauce”) to be more specific and distinguish it from many other dipping sauces in Vietnamese cuisine (see