Where does “ли́ляк” come from?

ли́ляк (Bulgarian) comes from Ottoman Turkish لیلاق, from Arabic لَيْلَك, from Classical Persian لِیلَک.

Ancestry of “ли́ляк”, step by step

Step	Language	Word	Meaning
1	Ottoman Turkish	لیلاق	lilac
2	Arabic	لَيْلَك	—
3	Classical Persian	لِیلَک	—