Definitions for "Translation unit"
(1) A source file together with all headers and source files included via the preprocessing directive #include, less any source files skipped by any of the conditional inclusion preprocessing directives. ANSI.
(Trados) A segment or sentence pair in source and target languages.
The standard term for a compilation unit. It refers to a single source file submitted to the compiler along with all files included by the compilation of that single source file (technically, the output of the preprocessor). A translation unit normally results in a single object file. Looking at it another way, a variable name explicitly declared static has the scope of its translation unit and can be used as a name for other objects, functions, and so on in other translation units in the same application.