Ma'anar ƙamus na "rol ɗin ganga" wani nau'in motsi ne na iska wanda jirgin sama ke yin cikakken jujjuyawar digiri 360 yayin da yake bin hanyar karkace, tare da hancin jirgin yana jujjuyawa akai-akai. Kalmar “ganga” tana nufin sifar hanyar da jirgin ke bi, wanda yayi kama da sifar silindari, ko ganga. Ana amfani da mashin ɗin sau da yawa a cikin nunin iska ko kuma a matsayin motsa jiki don gujewa jirgin da ke kai hari.