requin (ruh-KAN) - n., the great white shark (Carcharodon carcharias).
Or, sometimes, other sharks in the same family (such as the tiger shark or blue shark) that are found in tropical and temperate waters, but that wider sense is more technically called requiem sharks -- because of very occasionally attacking people. That wider sense makes some sense, given that requin in French is generically shark (from Old French reschignier, to grimace while bearing teeth, from a Germanic root meaning to split open), but properly speaking in English we use requin for just the great white.

Thanks, WikiMedia!
---L.
Or, sometimes, other sharks in the same family (such as the tiger shark or blue shark) that are found in tropical and temperate waters, but that wider sense is more technically called requiem sharks -- because of very occasionally attacking people. That wider sense makes some sense, given that requin in French is generically shark (from Old French reschignier, to grimace while bearing teeth, from a Germanic root meaning to split open), but properly speaking in English we use requin for just the great white.

Thanks, WikiMedia!
---L.