In the process of implementing a new computer language, the point at which the language is sufficiently effective that one can implement the language in itself. That is, for a new language called, hypothetically, FOOGOL, one has reached break-even when one can write a demonstration compiler for FOOGOL in FOOGOL, discard the original implementation language, and thereafter use working versions of FOOGOL to develop newer ones. This is an important milestone; see MFTL.
Since this entry was first written, several correspondents have reported that there actually was a compiler for a tiny Algol-like language called Foogol floating around on various VAXen in the early and mid-1980s. A FOOGOL implementation is available at the Retrocomputing Museum http://www.catb.org/retro/.