Where does “третман//tretman” come from?

третман//tretman (Serbo-Croatian) comes from French traitement, from Middle French traictement, from Middle French traicter, from Old French traiter, from Latin tractāre, from Latin tractō, from Latin -tō, from Latin -tus — Derives action nouns from verb roots.

Ancestry of “третман//tretman”, step by step

StepLanguageWordMeaning
1Frenchtraitementtreatment; processing
2Middle Frenchtraictementtreatment
3Middle Frenchtraicterto treat
4Old Frenchtraiter
5Latintractāre
6Latintractōto tug, drag or haul
7Latin-tōForms here
8Latin-tusForms the past participle of verbs; Forms...
9Proto-Italic-tus
10Proto-Indo-European-tusDerives action nouns from verb roots
Every word from Proto-Indo-European -tusEvery word from Latin -tusEvery word from Latin -tō