cil·i·um / ˈsilēəm/ • n. (usu. in pl. cil·i·a / ˈsilēə/ ) Biol. & Anat. a short hairlike vibrating structure. Cilia occur in large numbers on the surface of certain cells, either causing currents in the surrounding fluid, or, in some protozoans and other small organisms, providing propulsion. ∎  an eyelash, or a delicate hairlike structure that resembles one.DERIVATIVES: cil·i·at·ed / ˈsilēˌātid/ adj.cil·i·a·tion / ˌsilēˈāshən/ n.

cilium (pl. cilia) A short, hair-like appendage, normally 2–10μm long and about 0.5μm diameter, usually found in large numbers on those cells that have any at all. Cilia have a microtubular skeletal structure enclosed by an extension of the cell membrane. The microtubules are arranged in nine sets of doublets around the circumference, with two single tubules in the centre, the so-called ‘9 + 2’ construction. In certain protozoa, cilia function in locomotion and/or feeding. They generate currents in the fluid surrounding the cell by beating in a coordinated manner.

cilium (pl. cilia) A short, hair-like appendage, normally 2–10μm long and about 0.5μm in diameter, usually found in large numbers on those cells that have any at all. Cilia have a microtubular skeletal structure enclosed by an extension of the plasma membrane. The microtubules are typically arranged in 9 sets of doublets around the circumference, with 2 single tubules in the centre, the so-called ‘9 + 2’ construction. In certain protozoa, cilia function in locomotion and/or feeding. They generate currents in the fluid surrounding the cell by beating in a coordinated manner.

cilium (pl. cilia) A short minute hairlike structure (up to 10 μm long) present on the surface of many cells, notably in certain protozoans and some types of vertebrate epithelium. Cilia usually occur in large groups and are shorter than eukaryotic flagella, although both organelles have the same structure and are collectively termed undulipodia (see undulipodium). Beating of cilia can produce cell movement or create a current in fluid surrounding a cell. See also axoneme.

cilium (pl. cilia) Short, hair-like appendage, normally 2–10 μm long and about 0.5 μm in diameter, usually found in large numbers on those cells that have any at all. In certain protozoa, cilia function in locomotion and/or feeding. They generate currents in the fluid surrounding the cell by beating in a co-ordinated manner.