1. n. 1. A control file for a program, esp. a text file automatically read from each user's home directory and intended to be easily modified by the user in order to customize the program's behavior. Used to avoid hardcoded choices (see also dot file, rc file). 2. [techspeak] A report on the amounts of time spent in each routine of a program, used to find and tune away the hot spots in it. This sense is often verbed. Some profiling modes report units other than time (such as call counts) and/or report at granularities other than per-routine, but the idea is similar. 3.[techspeak] A subset of a standard used for a particular purpose. This sense confuses hackers who wander into the weird world of ISO standards no end! From Jargon Dictionary