pikometer

Pikometer is a fictional or non-SI unit of length used in speculative and educational contexts to describe extremely small distances. It is not recognized by the International System of Units, and there is no universally agreed magnitude for a pikometer. In various works, the term is defined differently, serving as a flexible label rather than a fixed standard.

The name resembles existing prefixes used for small lengths but has no formal meaning in SI. As a result, writers and educators may assign any value that suits their scenario, or use pikometer as a purely symbolic scale.

In science fiction and some thought experiments, a pikometer is invoked to discuss molecular or nanoscale phenomena, such as the dimensions of hypothetical devices or the spacing within complex structures. The unit is typically intended to emphasize a scale smaller than a nanometer while remaining distinct from established prefixes, but specific magnitudes vary by context.

In real-world science, measurements rely on recognized units such as the picometer (10^-12 m) and the femtometer (10^-15 m). The pikometer, by contrast, functions as a pedagogical or literary device to illustrate how units can be defined or renamed for particular problems.

Related units include picometer, femtometer, attometer, and nanometer.