Definition

1. Adjective:

   • (Of a firearm) Capable of firing repeatedly with a single pull of the trigger for each shot, automatically loading the next round but not firing it automatically. A semiautomatic weapon fires one bullet each time the trigger is pulled, without the need for manual reloading between shots.
   • Partially automatic; operating with some degree of automatic function but requiring human initiation for each cycle. This sense can extend beyond firearms to describe machinery or processes that are partly but not fully automatic.

2. Noun:

   • A firearm that operates in a semiautomatic manner. It typically refers to a pistol or rifle designed to fire, eject the spent cartridge case, and load a new cartridge from a magazine with each single trigger pull.

Usage Examples

• Adjective:

  • The police officer carried a semiautomatic pistol for duty.
  • This is a semiautomatic shotgun, not a fully automatic one.
  • The factory uses a semiautomatic packaging machine that requires an operator to start each cycle.

• Noun:

  • He owns a 9mm semiautomatic.
  • The suspect was armed with a semiautomatic and a large-capacity magazine.

Advanced Usage

• Technical Context: In firearm mechanics, "semiautomatic" specifically describes the self-loading action. The firing cycle (eject, load) is powered by the energy of the fired round (recoil or gas), but the trigger must be released and pulled again to fire the next round.
• Contrast with "Automatic": A key distinction is that a fully automatic firearm (a "machine gun") will continue to fire as long as the trigger is held down, while a semiautomatic fires only once per trigger pull.

Variants and Related Words

• Semiautomatically (adverb): In a semiautomatic manner.
  • The rifle fires semiautomatically.
• Autoloading (adjective): Another term for semiautomatic, emphasizing the automatic loading feature. Often used interchangeably.
  • An autoloading rifle.

Synonyms

• Self-loading (adjective): A synonym emphasizing the automatic loading mechanism.
• Autoloading (adjective): (As above).

Related Phrases

• Semiautomatic mode: A setting on some firearms (e.g., certain rifles) that allows them to operate as a semiautomatic.
  • Make sure the selector switch is on semiautomatic mode.
• Semiautomatic transmission: (In automotive contexts) A type of vehicle transmission that allows for manual gear selection but operates the clutch automatically. (Note: This is a compound term listed here as a related concept, not a direct definition of the headword "semiautomatic").

Adjective

1. (of firearms) capable of automatic loading and firing continuously
   • an autoloading rifle
2. partially automatic

Noun

1. a pistol that is a semiautomatic firearm capable of loading and firing continuously