Jack

Jack is a term with multiple distinct meanings in English, each of which is documented in reputable reference works.

1. Personal name

   • Origin: Derived from the medieval diminutive of the name John, which originates from the Hebrew name Yochanan meaning “Yahweh is gracious.”
   • Usage: Frequently used as a male given name in English‑speaking countries; also appears as a surname.

2. Mechanical device

   • Definition: A tool used to lift heavy objects, typically vehicles, by converting a small input force into a larger output force.
   • Common types:
     • Scissor jack – utilizes a screw mechanism.
     • Hydraulic jack – employs fluid pressure.
   • Applications: Automotive maintenance, industrial settings, and consumer goods.

3. Playing card

   • Description: One of the face cards in a standard 52‑card deck, representing a male servant or soldier.
   • Ranks: In most games, the jack ranks below the queen and above the ten; in some games (e.g., euchre) it may have a special rank.

4. Electrical connector

   • Definition: A female receptacle that receives a corresponding plug (male connector).
   • Examples: Audio jacks (3.5 mm), telephone jacks, and network jacks.

5. Other specialized uses

   • Jack (in sailing) – a flag flown from the bow of a vessel when anchored or moored.
   • Jack (in computer networking) – a port for connecting a network cable.
   • Jack (in plumbing) – a fitting for joining pipes.

Each of these meanings is established in dictionaries, technical manuals, and encyclopedic entries, confirming that “Jack” is a widely recognized term with multiple well‑documented senses.