Where does “letter agreement” come from?

letter agreement (English) comes from English agreement, from Middle English agrement, from Old French agrement, from Old French agreer, from Old French gré, from Latin grātum, from Latin grātus, from Proto-Italic grātos — to express approval; praise; to elevate.

letter agreement (English): An agreement, specifically a legally binding...

Definitions

  1. An agreement, specifically a legally binding...

Ancestry of “letter agreement”, step by step

letter agreement traces back through two separate lines of ancestry.

via English agreement

StepLanguageWordMeaning
1EnglishagreementAn understanding between entities to follow a...
2Middle EnglishagrementAn understanding, agreement, or state of mutual...
3Old Frenchagrementagreement; accord
4Old Frenchagreerto please; to be pleasing to
5Old Frenchgrépleasure, goodwill; will; step
6Latingrātum
7Latingrātuspleasing, acceptable, agreeable, welcome
8Proto-Italicgrātos
9Proto-Indo-Europeangʷr̥Htóspraised
10Proto-Indo-EuropeangʷerH-to express approval; praise; to elevate

via English letter

StepLanguageWordMeaning
1EnglishletterA symbol in an alphabet; A written or printed...
2Middle Englishletter
3Old Frenchletreletter
4Latinlitteraa letter of the alphabet; handwriting; letter,...
5Latinlītera
6Old Latinleitera
7Proto-Indo-Europeanh₂leyH-to smear
8Proto-Indo-Europeanleyh₂-to die, disapear; to avoid, elude, decline,...
Every word from Proto-Indo-European gʷerH-Every word from Proto-Indo-European gʷr̥HtósEvery word from Proto-Italic grātos