P
| "Paleface" | A new recruit or fresh fish |
| "Parley" | Term for a conference from the French word "parler" meaning "to speak" |
| "Parlor soldier" | Insult for soldiers of little merit or worth |
| "Patent Bureau" | Knapsack |
| "Peas on a trencher" | Breakfast call |
| "Pepperbox" | Pistol |
| "Pie eater" | Man from a rural area |
| "Possum" | A buddy or friend |
| "Pumpkin rinds" | Grumpy term for Lieutenants; name comes from their shoulder straps |