fascio

Fascio is an Italian noun that primarily denotes a bundle, sheaf, or cluster of things tied or grouped together. The plural form is fasci. In everyday language the word can refer to any collection or grouping, such as a fascio di legno (a bundle of wood) or fascio di carte (a stack of papers). The term also appears in technical and scientific contexts to indicate a beam or bundle of energy, particles, or other entities, for example fascio di luce (beam of light) or fascio di elettroni (beam of electrons).

In science and technology, fascio is used to describe a directed flow or concentration of something. In optics and particle physics it commonly means a beam, as in fascio di fotoni or fascio di particelle. In engineering, a convergent or parallel flow can be referred to as a fascio in informal usage, though more precise terms may be preferred in specialized fields.

In biology and medicine, fascio denotes a bundle of fibers or cells. For example, in anatomy a fascio di fibre can refer to a muscle fascicle or a nerve fascicle, describing the organized grouping of fibers within tissue. In botany, fascio vascolare refers to a vascular bundle in plant stems and leaves, a centralized arrangement of xylem and phloem.

Historically, the word is closely linked to the symbol fasce or fasci, a bundle of rods with an axe carried by magistrates in ancient Rome. The term inspired the name of the early 20th‑century Italian movement and ideology fascismo (fascism), whose name derives from fasci di combattimento, groups that promoted unity or national strength. The linguistic legacy of fascio thus spans everyday language, scientific terminology, and political history.