security blanket

Từ điển Việt Anh Việt 4in1 - English Vietnamese 4 in 1 Dictionary

seˈcurity ˌblanket BrE AmE noun [countable]
1. a piece of material that a child likes to hold, to comfort himself or herself
2. something that you have had for a long time, and that you use to make yourself feel less anxious