cadet vs second lieutenant

cadet

noun
  • A student at a military school who is training to be an officer. 

  • Junior. (See also the heraldic term cadency.) 

  • A younger or youngest son, who would not inherit as a firstborn son would. 

  • A young gentleman learning sheep farming at a station; also, any young man attached to a sheep station. 

  • A participant in a cadetship. 

second lieutenant

noun
  • The lowest rank of a commissioned army officer, below a lieutenant. 

  • The lowest rank of a commissioned officer in the United States Army, United States Air Force, or United States Marine Corps, below a first lieutenant. The rank of second lieutenant is equivalent to the naval rank of ensign. 

How often have the words cadet and second lieutenant occurred in a corpus of books? (source: Google Ngram Viewer )