Definition 1 (Noun): Referring to the bore diameter of a firearm, measuring 0.45 inches or approximately 11.4 millimeters.

Sample Sentence 1: I prefer using a .45 caliber handgun for self-defense.

Sample Sentence 2: The army adopted the .45 caliber pistol as its standard sidearm.

Definition 2 (Adjective): Describing something related to or designed for a firearm with a .45 caliber bore.

Sample Sentence 1: He modified his .45 caliber rifle to improve its accuracy.

Sample Sentence 2: We need to find a .45 caliber ammunition supplier for the shooting range.

Definition 3 (Noun, Local): Referring to a specific powerful revolver, typically known as a ".45 caliber."

Sample Sentence 1: Deputy John always carries his trusty .45 caliber on duty.

Sample Sentence 2: The old western movies often depict cowboys toting a .45 caliber on their hips.