nodul

Nodul is a term used in several languages to denote a small, rounded swelling or localized mass. In science, the word appears across disciplines with field-specific meanings. Etymologically it derives from Latin nodulus, meaning a small knot.

In medicine, nodules are discrete tissue enlargements that can arise in many organs. Examples include pulmonary nodules in the lungs, thyroid nodules, and skin nodules. Most nodules are benign, but some may indicate infection, inflammation, or malignancy and require imaging and, if needed, biopsy for assessment.

In botany, root nodules form on the roots of many legumes and house nitrogen-fixing bacteria. These nodules enable plants to obtain usable nitrogen from the atmosphere, contributing to soil fertility and agricultural productivity.

In geology and mineralogy, nodules or concretions are rounded masses within sedimentary rocks or sediments. They form by precipitation of minerals from groundwater or by replacement and grow into spherical or ovoid shapes. Common examples include calcite, carbonate, iron, and manganese nodules.

In materials science, the term nodular describes graphite that forms as round nodules in ductile iron, which improves toughness compared with irregular, flake-like graphite.

Because the word spans multiple domains, the exact meaning of nodul depends on context, but it generally refers to a localized, distinct mass or structure.