Morpheme is a minimal unit of meaning or grammatical function. There are two types of morphemes: free and bound morphemes.
Free morphemes are divided into two categories - lexical and functional morphemes.
Bound morphemes also fall into two groups - derivational and inflectional morphemes.
If you're interested, I will explain to you all of them, but for the purpose of your query, here's your answer:
Functional morphemes consist of the functional words in the language - conjunctions, prepositions, articles and pronouns. For example: 'and', 'near', above', 'in', 'the', 'but', 'on', 'that', etc.
Student or Learner