1.
If you calm down, or if someone calms you down, you become less angry, upset, or excited.
Calm down for a minute and listen to me...
Do not have a drink or take drugs to calm yourself down.
PHRASAL VERB: V P, V n P, also V P n (not pron)
2.
If things calm down, or someone or something calms things down, the amount of activity, trouble, or panic is reduced.
We will go back to normal when things calm down...
Neil Howorth, director of the academy, tried to calm things down.
= settle down
PHRASAL VERB: V P, V n P