1. adjective /flæŋk/
Maximum (of speed). Historically faster than full speed (the most a vessel can sustain without excessive engine wear or risk of damage), now frequently used interchangeably. Typically used in an emergency or during an attack (All ahead flank!).
2. noun /flæŋk/
a) The flesh between the last rib and the hip; the side.
Cautiously I approached the flank of the cliffs, where they terminated in an abrupt escarpment as though some all powerful hand had broken off a great section of rock and set it upon the surface of the earth.
b) A cut of meat from the flank of an animal.
3. verb /flæŋk/
a) To attack the flank(s) of something.
b) To defend the flank(s) of something.
Wikipedia foundation.