Where does “πηκτικός” come from?

πηκτικός (Ancient Greek) comes from Ancient Greek πήγνυμι, from Proto-Indo-European peh₂ǵ- — to attach.

πηκτικός (Ancient Greek): congealed, curdled; curdling

Definitions

Step	Language	Word	Meaning
1	Ancient Greek	πήγνυμι	I secure, stick in, fix on; I fasten, put...
2	Proto-Indo-European	peh₂ǵ-	to attach

πηκτικός — Etymology, Origin & Word History | Etymology Explorer