noun, masculine/bif.tɛk/plural: biftecks
beefsteak (a steak of beef)
Related: défendre son bifteck, gagner son bifteck
18th century, from English beefsteak with the cluster /fst/ reduced to /ft/ (or less often to /st/). The spelling was highly variable up into the 20th century until bifteck established itself, which is phonetic but adds the “un-French” -k, be it as a pseudo-English form or after the related steak (whose spelling remained unaltered).