On the basis of new data on diatom frustule functions, found in the field of nanotechnology, the conclusion was made about a multifunctional role of most frustule structural elements and their taking part in many vital functions of the diatom single-cell organism. The proposal on revision of the morphological terms for the diatom frustule description is put on the modern universal base. The concept on a possible approach to diatom functional morphology and the definitions of the diatom frustule basic element and morph of the diatom frustule for description of fine morphology are suggested. Some structures of frustule as velum, areola, stria are considered in the light of function morphology.