kirtle vs undergarment

kirtle

noun
  • A woman's gown; a woman's outer petticoat or skirt. 

  • A knee-length tunic. 

  • A short jacket. 

verb
  • To clothe or cover with, or as if with, a kirtle; to hitch up (a long garment) to the length of a kirtle. 

undergarment

noun
  • Any garment worn underneath others, especially one worn next to the skin; an item of underwear. 

  • Temple garments worn by the followers of the Church of Jesus Christ of Latter-day Saints. 

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