definition of
settle down

[1] #1 settle down v. settle into a position, usually on a surface or ground; "dust settled on the roofs". wn

[2] #2 settle down v. become settled or established and stable in one's residence or life style; "He finally settled down". wn

[3] #3 settle down v. become quiet or calm, especially after a state of agitation; "After the fight both men need to cool off."; "It took a while after the baby was born for things to settle down again.". wn