* It's a misspelling. Perhaps you meant a similar-sounding word like "tranquilo" (Spanish for calm or peaceful) or "tranquille" (French for calm).
* It's a slang term or regional dialect word. Without more context, it's difficult to determine its meaning.
* It's a made-up word.
Could you provide more context about where you encountered this word? For example, what language was it used in, and what was the surrounding text or conversation? This would help me understand what "trenkilo" might mean.