T-junction vs cloverleaf

T-junction

noun
  • A similarly shaped section in a pipe, etc. 

  • An intersection of routes where one road terminates as it joins a (usually higher priority) road at approximately 90°. In most countries, a give way or stop road sign will be seen at a T-junction. 

cloverleaf

noun
  • (with plural cloverleafs or cloverleaves) A cloverleaf interchange. 

  • The leaf of a clover plant 

adj
  • In the form of the leaf of a clover plant; cloverleafed. 

verb
  • To turn by following a cloverleaf, or as if by following one. 

How often have the words T-junction and cloverleaf occurred in a corpus of books? (source: Google Ngram Viewer )