Peil

Peil is a Dutch noun meaning level, height, or reference height. It is used to describe the vertical position of surfaces or substances, notably water. In hydrology and civil engineering, terms such as waterpeil (water level), peilhoogte (elevation), and peilstand (level reading) describe the current height of water or ground relative to a datum. Measurements are taken at designated peilpunten (reference points) along rivers, canals, and coastlines.

The Netherlands uses Normaal Amsterdams Peil (NAP) as a national vertical datum. Elevations and depths in maps, dikes, and flood-control infrastructure are stated relative to NAP. In other contexts, peil can refer to a benchmark or marker that fixes a local height for surveying.

A peil can be an instrument or marker, such as a peilstok (sounding rod) or a peilsensor, used to determine or monitor the level of water, sediment, or other substances in tanks, wells, or reservoirs.

The verb peilen means to measure the level or depth, and peiling is the act of performing such a measurement. The concept is widespread in Dutch geography, civil engineering, boating, and flood management, and the word also appears in metaphorical expressions for setting a standard or benchmark.

In sum, peil denotes a reference level or the measurement of that level, with practical importance in water management, surveying, and mapping.