Where does “дискусия” come from?

дискусия (Bulgarian) comes from French discussion, from Latin discussiō, from Latin -tiō, from Latin dissertātiō, from Latin dissertus, from Latin disserere, from Latin dis-, from Latin calceus — small stone, pebble; gravel, rubble.

Ancestry of “дискусия”, step by step

дискусия traces back through 3 separate lines of ancestry.

via French discussion

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

via Russian дискуссия

Step	Language	Word	Meaning
1	Russian	дискуссия	discussion

via German Diskussion

Step	Language	Word	Meaning
1	German	Diskussion	discussion

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