cp

Cp is a two-letter symbol that appears in several different fields, with the meaning determined by context. It is commonly encountered in computing, science, and statistics.

In computing, cp is the standard Unix-like command used to copy files and directories. Typical usage is cp source destination, with options such as -r for recursive copying, -a to preserve attributes, and -i to prompt before overwriting. It is a basic file-management tool found on most Linux and macOS systems, and there are analogous commands in other operating systems.

In thermodynamics and physical chemistry, Cp denotes the molar heat capacity at constant pressure, often written as Cp,m for molar or Cp for a per-mass basis in some contexts. It describes how much energy is required to raise the temperature of a substance by one kelvin at constant pressure. For many ideal gases, Cp exceeds Cv (the constant-volume counterpart) by the gas constant R, reflecting the additional work of expansion at constant pressure.

In statistics, Cp refers to Mallows’ Cp, a model-selection criterion used in linear regression. It assesses the trade-off between goodness of fit and model complexity, helping to identify models that balance bias and variance. Lower Cp values near the number of parameters plus one generally indicate more reliable models.

In linguistics, CP (uppercase) stands for complementizer phrase, a theoretical syntactic projection that hosts complementizers and marks clause types. While the standard abbreviation is CP, some discussions may encounter Cp variants in informal writing.

Because Cp has multiple legitimate meanings across domains, clarity depends on context. When encountering Cp, consider the surrounding topic to determine whether it refers to computing, thermodynamics, statistics, linguistics, or another field.