Where does “ship of the line ensign” come from?

ship of the line ensign (English) comes from English ensign, from Middle English ensigne, from Old French enseigne, from Latin īnsignia.

ship of the line ensign (English): Junior officer rank used in the navies of some Romance-speaking countries, usually equal in rank to the British rank of sub-lieutenant or the American rank of lieutenant junior grade

Definitions

  1. Junior officer rank used in the navies of some Romance-speaking countries, usually equal in rank to the British rank of sub-lieutenant or the American rank of lieutenant junior grade

Ancestry of “ship of the line ensign”, step by step

ship of the line ensign traces back through two separate lines of ancestry.

via English ensign

StepLanguageWordMeaning
1EnglishensignA badge of office, rank, or power; The lowest...
2Middle Englishensigne
3Old Frenchenseigne
4Latinīnsignia

via English ship of the line

StepLanguageWordMeaning
1Englishship of the lineA large square-rigged warship large enough to have a place in the line of battle, with up to 140 guns on at least two decks. A capital ship from the age of sail, superior to a frigate; usually, a seventy-four, or three-decker
Every word from Latin īnsigniaEvery word from Old French enseigneEvery word from Middle English ensigne