Here's why:
* Noun: A word that names a person, place, thing, or idea. "Daedalus" and "Icarus" are both names of people.
* Phrase: A group of words that act as a single unit.
* Noun Phrase: A phrase that functions as a noun. In this case, the entire phrase "Daedalus and his son Icarus" refers to two people and acts as the subject of a sentence (e.g., "Daedalus and his son Icarus were famous for their ingenuity.")