Where does “estension” come from?

estension (Old French) comes from Latin extensio, from Latin -tiō, from Latin dissertātiō, from Latin dissertus, from Latin disserere, from Latin dis-, from Latin calceus, from Latin calx — small stone, pebble; gravel, rubble.

Ancestry of “estension”, step by step

estension traces back through two separate lines of ancestry.

via Latin extensio

Step	Language	Word	Meaning
1	Latin	extensio	extension, stretching; swelling, tumour
2	Latin	-tiō	tion, -ation, -ing
3	Latin	dissertātiō	(spoken) dissertation, discourse, disquisition
4	Latin	dissertus	arranged, disposed; explained
5	Latin	disserere	second-person singular future passive indicative...
6	Latin	dis-	asunder, apart, in two; reversal, removal;...
7	Latin	calceus	shoe
8	Latin	calx	limestone; chalk; the finish line
9	Ancient Greek	χάλιξ	small stone, pebble; gravel, rubble

via Latin extentio

Step	Language	Word	Meaning
1	Latin	extentio	extension

Words derived from “estension”

Every word from Ancient Greek χάλιξ →Every word from Latin -tiō →Every word from Latin dis- →