From Longman Dictionary of Contemporary Englishlambswoollambs‧wool /ˈlæmzwʊl/ noun [uncountable] soft wool from lambs, used for making clotheslambswool jumper/sweater/blanket etc
Examples from the Corpus
lambswool• a lambswool sweaterlambswool jumper/sweater/blanket etc• Left Debenhams lambswool jumper, £24.99; cotton chambray shirt, £15.99; tie, £7.99. 