Kalmar "bast fiber" tana nufin nau'in fiber da ake samu daga phloem ko haushi na wasu tsire-tsire, kamar flax, hemp, jute, ramie, da nettle. Waɗannan zaruruwa suna da tsayi, da ƙarfi, kuma masu sassauƙa, kuma ana amfani da su wajen kera masaku, igiyoyi, igiya, takarda, da sauran kayayyaki. Sunan "bast" ya fito daga tsohuwar kalmar Ingilishi "bæst," wanda ke nufin "bawon ciki."
