a slender and greatly elongated substance capable of being spun into yarn

having a single strand

one of the parallel filaments projecting from the main shaft of a feather

filaments from a web that was spun by a spider

one of two identical strands into which a chromosome splits during mitosis

one of many contractile filaments that make up a striated muscle fiber

any of various slender filaments that function as roots in mosses and ferns and fungi etc