rheumatism weed n 1: Canadian dogbane yielding a tough fiber used as cordage by native Americans; used in folk medicine for pain or inflammation in joints [syn: {Indian hemp}, {Apocynum cannabinum}] 2: North American perennial having pinkish flowers in loose cymes; used in folk medicine for pain or inflammation in joints [syn: {common dogbane}, {spreading dogbane}, {Apocynum androsaemifolium}]