Astern and To the rear

Astern adverb - Near, toward, or in the stern of a ship or the tail of an aircraft.

To the rear and astern are semantically related in abaft topic. In some cases you can use "To the rear" instead the word "Astern" as an adjective or an adverb, when it comes to topics like aft.

Astern and to the rear are semantically related in abaft topic. You can use "Astern" instead the phrase "To the rear" as an adjective or an adverb, if it concerns topics such as aft.