1. arcade - A vaulted passageway or street; a roofed passageway having shops, etc., opening from it.
2. archaic - Antiquated
3. archaism - Obsolescence.
4. archangel - An angel of high rank.
5. archbishop - The chief of the bishops of an ecclesiastical province in the Greek, Roman, and Anglican church.
6. archdeacon - A high official administrator of the affairs of a diocese.
7. archaeology - The branch of anthropology concerned with the systematic investigation of the relics of man.
8. archetype - A prototype.
9. archipelago - Any large body of water studded with islands, or the islands collectively themselves.
10. ardent - Burning with passion.
11. ardor - Intensity of passion or affection.
12. arid - Very dry.
13. aristocracy - A hereditary nobility
14. aristocrat - A hereditary noble or one nearly connected with nobility.
15. armada - A fleet of war-vessels.