garment vs piece of clothing

garment

noun
  • A single item of clothing. 

  • The visible exterior in which a thing is invested or embodied. 

verb
  • To clothe in a garment. 

piece of clothing

noun
  • An item of clothing; any item, such as a shirt or a sock, that constitutes clothing. 

How often have the words garment and piece of clothing occurred in a corpus of books? (source: Google Ngram Viewer )