To settle down is to start a calm steady life in one place, often with a family. Settle down and have children, ready to settle down, never settle down.
It carries an idea of the wandering being over, which is why it is said of people who have travelled or played the field. A second sense is simply to become quiet, so a class can settle down too.
1phrasesettle downTo start a calm steady life in one place, often with a family.
“He came back at forty and decided to settle down.”
settle down is a phrase.
Practised in Family & People, Phrasal Verbs