Where does “Ancestor X” come from?

Ancestor X (English) comes from English ancestor, from Middle English auncestre, from Old French ancessor, from Latin antecessor, from Latin ante, from Ancient Greek κλίσις, from Ancient Greek -σῐς, from Ancient Greek -τις — Derives abstract/action nouns from verb roots.

Ancestor X (English): The hypothetical ancestral species that is the most recent and last common ancestor of Homo sapiens, Homo neanderthalensis — the Neanderthals, Homo longi}} — the Denisovans

Definitions

The hypothetical ancestral species that is the most recent and last common ancestor of Homo sapiens, Homo neanderthalensis — the Neanderthals, Homo longi}} — the Denisovans

Ancestry of “Ancestor X”, step by step

Ancestor X traces back through two separate lines of ancestry.

via English ancestor

Step	Language	Word	Meaning
1	English	ancestor	One from whom a person is descended, whether on...
2	Middle English	auncestre	An ancestor or progenitor; someone that a person is descended from
3	Old French	ancessor	ancestor
4	Latin	antecessor	predecessor; vanguard, scout
5	Latin	ante	before, in front, forwards; before; before,...
6	Ancient Greek	κλίσις	bending, inclination; a lying down; a place for...
7	Ancient Greek	-σῐς	"suffix forming nouns"
8	Ancient Greek	-τις	retained after dentals
9	Proto-Indo-European	-tis	Derives abstract/action nouns from verb roots

via English X

Step	Language	Word	Meaning
1	English	X	An unknown quantity or unknown value; A variable...
2	English	Christ	A figure or other artistic depiction of Jesus...
3	Middle English	Crist	(Jesus) Christ
4	Old English	Crīst	Christ
5	Latin	Chrīstus	—
6	Ancient Greek	Χριστός	anointed; messiah; annointed, the annointed one,...
7	Ancient Greek	χρίω	to rub or smear (especially the body) with oil or unguents; to anoint
8	Proto-Indo-European	gʰrēy-	to smear; to paint, streak, smear
9	Proto-Indo-European	gʰer-	to rub; to stroke; to grind

Every word from Proto-Indo-European -tis →Every word from Ancient Greek -σῐς →Every word from Ancient Greek κλίσις →