jackknife

Thân thiện

A diver performs a perfect jackknife from the high diving board.

Definition

1. Noun:

   • A type of dive: A dive in which the diver bends at the waist to touch the ankles or shins with the hands before straightening the body to enter the water.
   • A type of knife: A large pocketknife with one or more folding blades.

2. Verb:

   • To perform a jackknife dive: To dive into the water by bending the body sharply at the waist, as in the jackknife dive.
   • To fold or bend sharply: (Especially of an articulated vehicle like a truck and trailer) to fold or bend at a sharp angle, typically in an uncontrolled way during an accident.

Usage Examples

• Noun (Dive): The Olympic diver executed a perfect jackknife from the 10-meter platform.Her best dive is the jackknife, where she tucks tightly before entering the water.

• Noun (Knife): He used his sturdy jackknife to cut the rope.The old sailor always carried a jackknife in his pocket.

• Verb (Dive): The swimmer will jackknife off the starting block.She practiced for hours to learn how to jackknife correctly.

• Verb (Vehicle accident): The truck's brakes failed, causing it to jackknife across the icy highway.When the trailer skidded, the entire rig began to jackknife.

Advanced Usage

• "to jackknife" (intransitive verb, vehicle): This is a specialized but common usage describing the dangerous folding action of a long vehicle.
• Figurative use for bending: While less common, it can describe any sharp, angular bend.

Variants and Related Words

• Pocketknife (noun): A more general term for a small folding knife. A jackknife is a specific, often larger, type of pocketknife.
• Swiss Army knife (noun): A proprietary brand of multi-tool pocketknife.
• Jackknifing (noun/gerund): The action or process of a vehicle jackknifing.

Synonyms

• For the dive: Pike dive (a similar but not identical diving position where the body is bent at the hips with legs straight).
• For the knife: Folding knife, clasp knife.
• For the vehicle action: Fold, hinge, buckle (in this specific context).

Related Phrasal Verbs

(This word does not commonly form phrasal verbs.)

Related Idioms

(There are no common idioms using the word "jackknife.")

Học thuật

Noun

1. a dive in which the diver bends to touch the ankles before straightening out
2. a large knife with one or more folding blades

Verb

1. dive into the water bending the body at the waist at a right angle, like a jackknife

Từ đồng nghĩa

• clasp knife