Where does “Penrose diagram” come from?

Penrose diagram (English) comes from English diagram, from French diagramme, from Italian diagramma, from Ancient Greek διάγραμμα, from Ancient Greek δῐᾰ-, from Ancient Greek διά, from Proto-Indo-European dwís, from Proto-Indo-European dwóh₁ — two.

Penrose diagram (English): a two-dimensional diagram capturing the causal...

Definitions

  1. a two-dimensional diagram capturing the causal...

Ancestry of “Penrose diagram”, step by step

Penrose diagram traces back through two separate lines of ancestry.

via English diagram

StepLanguageWordMeaning
1EnglishdiagramA plan, drawing, sketch or outline to show how...
2Frenchdiagrammediagram
3Italiandiagrammadiagram; chart; graph
4Ancient GreekδιάγραμμαThat which is marked out in lines, plan, diagram
5Ancient Greekδῐᾰ-apart; through, across; through; in different...
6Ancient Greekδιάthroughout
7Proto-Indo-Europeandwístwice, doubly; in two
8Proto-Indo-Europeandwóh₁two

via English Penrose

StepLanguageWordMeaning
1EnglishPenroseOS grid ref SW8770
Every word from Proto-Indo-European dwóh₁Every word from Ancient Greek δῐᾰ-Every word from Proto-Indo-European dwís