r1 is an affix/combining form for zi'evla word r2=z1, form/properties r3.
From zi'evla+rafsi. zi'evla are predicate words of an open class in Lojban, defined by their morphology. Compare zevlyjvo, a compound word made of one or more zevlyrafsi. See also zevla, lujvo, brapagjvo, cmapagjvo, fu'ivla.