Parts of speech are a category of words that have similar use and function.
Words are the smallest part of sentence that has distinctive meaning and function. Words are divided into 8 categories based on the similar grammatical properties.
The 8 parts of speech are as follows:
Apart from these eight parts of speech, there is another category of words that has similar properties and they are called Article or Determiner.
Two get mastery over English Grammar, you should also know about:
English Grammar: Parts of Speech