Definitions of sideways:

• adjective:   (of movement) at an angle
• adverb:   toward one side

  Example: "The car slipped sideways into the ditch"

• adverb:   with one side forward or to the front

  Example: "Turned sideways to show the profile"

• adverb:   to, toward or at one side
• adverb:   from the side; obliquely

  Example: "A picture lit sideways"