soft spot

This term is most frequently used as an idiom to describe an affectionate bias or a specific vulnerability to a person or thing. It suggests a tenderness that overrides logic or strictness, often resulting in a tendency to be more lenient or indulgent toward the object of affection.

In a medical context, the term refers specifically to the fontanelles of an infant. While the idiomatic use is common in casual and semi-formal conversation, the anatomical use is technical and descriptive, lacking any emotional connotation.