Where does “ребристый” come from?

ребристый (Russian) comes from Russian ребро, from Old East Slavic ребро, from Proto-Slavic rebrò, from Proto-Balto-Slavic *rébran, from Proto-Indo-European h₁rebʰ- — to cover, to roof; rib.

ребристый (Russian): ribbed; ribby

Definitions

ribbed; ribby

Ancestry of “ребристый”, step by step

Step	Language	Word	Meaning
1	Russian	ребро	rib; edge, verge, arc; roentgenizdat; music...
2	Old East Slavic	ребро	—
3	Proto-Slavic	rebrò	rib
4	Proto-Balto-Slavic	*rébran	rib
5	Proto-Indo-European	h₁rebʰ-	to cover, to roof; rib

Every word from Proto-Indo-European h₁rebʰ- →Every word from Proto-Balto-Slavic *rébran →Every word from Proto-Slavic rebrò →