Bilateral symmetry is similar to anatomical parts which are arranged on either side of a median axis. It makes only one plane divide individuals into essentially identical halves.
It also means that the left side of the mirror is the right side.
The body structure of the octopus contains eight arms and bulbous heads which can be arranged to opposite sides of a median axis.
Thus their body is bilaterally symmetric.
These organisms have a preferred locomotory direction with respect to body orientation.