In school, we learn that there are eight parts of speech: noun, verb, adjective, adverb, pronoun, preposition, conjunction, and interjection. Modern grammarians recognise a couple of others: determiners and particles.
Phrasal verbs are idioms combining a verb and a particle. Some examples are “slow down,” “stand up,” “turn over.” Those particles (down, up, over) all look like prepositions, but that’s not how they function.
In “Jack and Jill went up the hill,” “hill” is the object of “up”. In “Stand up when a lady enters the room,” there is no object of “up.”
Determiner is a useful basket category that includes articles, and many types of adjectives, such as demonstratives (this, that, these, those), and quantifiers (some, many, all). The reason for making them a separate category is to simplify the statement of some grammar rules. In my computational linguist job, I found that I could get more precise and significant parses of sentences by using those parts of speech. The determiners that you can use with mass nouns (such as milk, patience, and time, are not always the same ones you can use with count nouns (such as book, event, and second). For us, part of speech was just a convenient arbitrary label, to be used in whatever way improved the analysis.