Across
- 3. To strengthen or reinforce something for protection.
- 5. Applying science and mathematics to design and construct machines.
- 8. A heavily fortified and secure stronghold or structure.
- 9. A system that uses radio waves to detect other objects.
- 10. Devices that produce heat, or a bright light used for signaling.
- 11. Usual or common.
- 12. Firm and not likely to give way.
Down
- 1. Changes or alterations made to something to improve or adapt it.
- 2. Relating to something that occurs in the air.
- 4. The ability to withstand for a long time.
- 6. Relating to buying and selling for profit.
- 7. Strips of material dispersed into the air to distract enemy radar systems.