babe in arms
An infant, as in She's been a family friend since I was a babe in arms. Although the word “babe” for baby has been used since the 1300s, this phrase describing a child too young to walk (and hence having to be carried) dates only from about 1900.
Examples from the Web for babe in arms
Historical Examples of babe in arms
There were a half dozen of them—two men, three females, and one babe-in-arms.Quest of the Golden Ape