blanket term vs umbrella term

blanket term

noun
  • A word or phrase that is used to describe multiple groups of related things. The degree of relation may vary. Blanket terms often trade specificity for ease-of-use; in other words, a blanket term by itself gives little detail about the things that it describes or the relationships between them, but is easy to say and remember. Blanket terms often originate as slang, and eventually become integrated into the general vocabulary. 

umbrella term

noun
  • A term used to cover a broad category of things rather than a single specific item. 

How often have the words blanket term and umbrella term occurred in a corpus of books? (source: Google Ngram Viewer )