D defs.my
Entry 2 senses Webster, 1913

Coo

/ko͞o/ · IPA /ku/
01 v. i. To make a low repeated cry or sound, like the characteristic note of pigeons or doves.
imp. & p. p. Cooed; p. pr. & vb. n. Cooing
  1. 1.
    To make a low repeated cry or sound, like the characteristic note of pigeons or doves.
    “The stockdove only through the forest cooes, Mournfully hoarse.” Thomson.
  2. 2.
    To show affection; to act in a loving way. See under Bill, v. i. See: Bill