exclam.
    - used to give an affirmative response.
 - responding to someone addressing one or attracting one's attention.
 - questioning a remark.
 - expressing delight.
 
n.
 (pl. yeses or yesses)
 an affirmative answer, decision, or vote.
 
  Etymology
  OE gēse, gīse, prob. from an unrecorded phr. meaning ‘may it be so’.