What is "rotane"

n. (context organic compound English) Any of a class of hydrocarbons consisting of spiro-linked cyclopropane units only, but with a common [n]membered ring in the middle; they are named ''n-rotanes'' depending on the size of the inner ring

The rotanes are a class of hydrocarbon consisting of spiro-linked cyclopropane units having a common n-membered ring in the middle.

They are named [n]rotanes depending on the number of carbon atoms in the middle ring. The simplest of them, [3]rotane, is a branched triangulane.