ENGLISH
REFERENCE

semi

n. · adv.
US //ˈsɛmaɪ// UK //sˈɛmi// se·mi
  1. 1 a house (n.)
    B1 Intermediate British English Informal

    a house that is joined to another house on one side.

    a semi-detached house, sharing one common wall with an adjacent property.

    Example

    They live in a quiet semi at the end of the street.

    Example

    The developer converted the Victorian semi into two separate apartments, though the shared wall required significant soundproofing.

    Usage

    Commonly used in British and Australian English to describe residential property.
    • semi detached
  2. 2 a large truck (n.)
    B1 Intermediate American English Informal

    a very large truck used for carrying goods over long distances.

    a semi-trailer or tractor-trailer used for heavy haulage.

    Example

    The highway was full of semis carrying supplies to the city.

    Example

    The driver struggled to manoeuvre the semi through the narrow industrial estate, eventually requiring a spotter to assist with the tight turn.

    Usage

    Primarily North American usage; the British equivalent is 'artic'.
    • artic
    • tractor trailer
    • eighteen wheeler
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  1. 3 sports match (n.)
    B1 Intermediate Informal Sport

    a match or race that comes just before the final.

    a semi-final round in a knockout competition.

    Example

    Our team won the semi and will play for the trophy on Sunday.

    Example

    After a gruelling semi that went into extra time, the players had only three days to recover before the championship match.
    • semi final
  2. 4 finance/tech (n.)
    C1 Advanced Informal Technical Computing

    companies that make computer chips.

    shorthand for semiconductor companies or their stocks.

    Example

    Investors are buying semis because of the high demand for AI chips.

    Example

    The portfolio manager increased exposure to the semis, betting that the supply chain constraints would ease by the third quarter.
  3. 5 firearms (n.)
    C1 Advanced Slang

    a gun that fires one bullet each time you pull the trigger.

    a semiautomatic firearm.

    Example

    The police found a semi hidden in the back of the car.

    Example

    The legislation specifically targets the sale of high-capacity semis to unlicensed individuals.
    • semiautomatic
  4. 6 partly (adv.)
    B2 Upper Intermediate Informal

    partly or somewhat.

    to some extent; partially.

    Example

    I was only semi-conscious when the alarm went off this morning.

    Example

    The project was only semi-successful, as it met the technical requirements but failed to gain traction with the target audience.

    Usage

    Usually functions as a prefix, but used as a standalone adverb in very casual speech.
Origin

The prefix semi- (from Latin) used as a noun.

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