The story
- Proto-Indo-European*h₁éǵʰ
- Proto-Indo-European*h₁éǵʰs
- Proto-Italic*eks
- Latinex
- Latinex-
- Proto-Indo-European*pleth₂-?
- Proto-Indo-European*pel-?
- Proto-Indo-European*pleh₂-
- Proto-Indo-European*pl̥h₂nós
- Proto-Italic*plānos
- Latinplānus
- Latinexplānō
- Latinexplānātor
- Late Latinexplānātōrius
- English todayexplanatory
From Late Latin explānātōrius, from Latin explānāt-, past-participle stem of explānāre (“to explain”). Displaced Old English ġereclīċ.
Etymology from Wiktionary, CC BY-SA 4.0.