bolt-onnoun/bəʊlt ˈɒn/

• 1

  An accessory that can be bolted on or otherwise attached.

  • Some guitars have the neck glued to the body (Les Pauls), some are bolted on (Fenders), and in some the neck is part of one piece of wood that extends through the body (Jackson). The theory of the neck through the body design is that if the pickups, bridge, and the strings (from tuners to tailpiece) are mounted on the same piece of wood, sustain will be greatly enhanced. In practice, a well joined glue-on and a properly fitted bolt-on will sustain just as well.
  • I would draw a distinction between transplants and cross-fertilisation. […] Cross-fertilisation implies a different, more indirect process. It implies that an external stimulus promotes an evolution within the receiving legal system. The evolution involves an internal adaptation by the receiving legal system in its own way. The new development is a distinctive but organic product of that system rather than a bolt-on.
• 2

  A functionality or service that can be added to an existing arrangement or plan (for example, a mobile telephone subscription).

  • [I]f an innovation has reached the maturity stage of the product life-cycle, then perhaps its functionality will be developed to provide a ‘bolt-on’, with the core of the innovation remaining essentially the same. A classic example of a sustained innovation is the mobile phone, where functionality is increased by adding on extra capabilities, such as video, Internet acss, GPS tracking systems, music, and email.
  • PureGym (puregym.com), which has more than 200 gyms across Britain, charges from £8.99 to £17.99 a month, with "bolt ons" available.
• 3

  slangA breast implant.

bolt-onadj/bəʊlt ˈɒn/

• 1

  Of an accessory: capable of being bolted on or otherwise attached.

  • [T]he first model of this now most famous line of related types, the [Gibson] Les Paul also appeared in 1952, […] The trapeze style tailpiece and combined bar bridge was also fitted, although this gave way to a bolt-on bar bridge by 1953.
  • Marketing is not an option, a bolt-on activity, or for moments when 'time allows'; it must be present all the time as the company goes about its business.
• 2

  computingengineeringmathematicsUsed to extend an existing system, operating as an add-on or plug-in.

  • This week we take a close look at four top contenders in the multitasking arena […] All the multitasking systems available for microcomputers today fall into one of two distinct categories: "bolt-on" multitaskers, which add multitasking to an operating system (DOS, for example) that originally executed one task at a time; and "built-in" multitaskers, which are part of the operating system by design.
  • Enhanced Data Rates for Global Evolution (EDGE), also known as Enhanced GPRS (EGPRS), is a digital mobile phone technology which acts as a bolt-on enhancement to 2G and 2.5G General Packet Radio Service (GPRS) networks.