mi·celle 
(mī-sĕl)
(mī-sĕl)n.
1. A submicroscopic aggregation of molecules, as a droplet in a colloidal system.
2. An organic particle of colloidal size found in coal.
3. A coherent strand or structure in natural or synthetic fibers.
[New Latin mīcella, from Latin mīca, grain.]
mi·cellar (-sĕlər) adj.