The other idiomatic meaning of to settle down is usually used when someone stops moving around in his life and finally stays in one place or focuses on one thing. When we are young, many of us move from place to place and travel around a lot. When we get older, however, we stay in one place, maybe buy a house, and perhaps get married and start a family; this is called settling down. It means to stop being restless or moving around too much in our lives.
This can also apply to someone who tries many kinds of jobs and when he gets older, decides to stay in one job that is stable and dependable so he can then provide for his family. Basically, we are restless when we are young, then we settle down when we get older.
However, some people never settle down. In fact, it's against their philosophy in life to ever settle down. For them, settling down means the end of youth and the excitement of life, which they think should last forever. But, that's another issue and another blog.
Whatever your opinion is on the topic, you've probably heard your own parents or someone else's parents repeatedly tell their adult kids that it's time to settle down.
Mother: So, how are you and Amy doing?
Son: We're doing alright.
Mother: Do I hear wedding bells?
Son: Uh, not yet.
Mother: I thought you guys seemed serious.
Son: We are; we just haven't talk about that yet.
Mother: Well, you know you're not getting any younger. You need to start thinking about settling down.
Son: I know, mom. I'll settle down when I'm ready. I'm not doing it just because I'm 32.
Mother: I'm just saying; you need to start seriously thinking about it.
Son: Alright. alright. ...
perhaps - maybe
restless - without rest; moving around a lot
youth - the time when you are young
Alright everyone, I hope you get to speak English a lot today.