When birds such as doves and pigeons coo, they make a low soft sound.

to speak in a soft, gentle, or loving way

The baby lay in his cot, cooing and gurgling. 婴儿躺在自己的小床上，咿咿呀呀，咯咯笑着。

It's sickening the way she coos over those cats of hers. 她对她那些猫柔声低语的样子令人作呕。

[ + speech ] "How wonderful to see you again, darling," she cooed. “又见到你真高兴，亲爱的，”她柔声低语道。

abbreviation for chief operating officer : the manager in an organization who is responsible for how the whole organization is run

Most recently, he was COO of IFS Engineering. 就在前不久，他还是IFS 工程公司的首席运营官。