Definitions of afield:

• adverb:   off the subject; beyond the point at issue

  Example: "Such digressions can lead us too far afield"

• adverb:   in or into a field (especially a field of battle)

  Example: "The armies were afield, challenging the enemy's advance"

• adverb:   far away from home or one's usual surroundings

  Example: "Looking afield for new lands to conquer- R.A.Hall"