to go to bed; to go to sleep; to fall asleep
to be laid up (with a cold); to be ill in bed
赤ちゃんがやっと寝付いた。
The baby finally fell asleep.
子どもは夜10時には寝付いている。
The kids are already asleep by ten at night.
疲れて帰った日は、布団に入るとすぐに寝付く。
On days I come home tired, I fall asleep as soon as I get into bed.