| FIR | worship of fire |
|---|---|
| FIR | a portable gun |
| FIR | the luminous center of a nuclear explosion |
| FIR | a ball of fire (such as the sun or a ball-shaped discharge of lightning) |
| FIR | a highly energetic and indefatigable person |
| FIR | an especially luminous meteor (sometimes exploding) |
| FIR | an artillery base to support advancing troops |
| FIR | tropical American flycatcher found as far north as southern Texas and Arizona |
| FIR | eastern subspecies of northern oriole |
| FIR | the male is bright red with black wings and tail |
| FIR | a boat equipped to fight fires on ships or along a waterfront |
| FIR | a bomb with incendiary effects |