nonweighable

Nonweighable is a rarely used adjective applied to objects, substances, or quantities that cannot be weighed by conventional weighing methods. In a general sense, it describes scenarios where a precise mass measurement is not feasible with standard scales due to physical properties, extreme smallness, or measurement limitations. The term does not have a formal, widely adopted definition in metrology, but it appears in technical writings, thought experiments, or discussions that emphasize the limits of conventional weighing.

In physics, weight and mass are related but distinct: weight depends on the gravitational field, while mass is an intrinsic property. Some entities are considered nonweighable by traditional balances because they have zero rest mass or do not present a well-defined inertial mass in a given context. For example, photons have no rest mass and are not weighed on a standard balance, though their energy and momentum can be studied through other means. More practically, extremely small masses near or below the sensitivity of available scales—such as nano- or microgram ranges—may be described as effectively nonweighable with ordinary equipment, requiring specialized instruments or methods to determine their properties.

Beyond physical measurement, the term is sometimes used metaphorically to describe intangible items or digital assets whose value cannot be linked to physical mass, or to emphasize measurement limits in data-driven contexts.

See also: metrology, weighing, scale, mass, photon.