Ad hoc is a Latin phrase meaning "for this". In English, it generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes (compare with a priori).
Common examples are ad hoc organizations, committees, and commissions created at the national or international level for a specific task. In other fields, the term could refer, for example, to a military unit created under special circumstances, a tailor-made suit, a handcrafted network protocol, or a purpose-specific equation.
Ad hoc can also mean makeshift solutions, shifting contexts to create new meanings, inadequate planning, or improvised events.
Ad hoc hypothesis
In science and philosophy, ad hoc means the addition of extraneous hypotheses to a theory to save it from being falsified. Ad hoc hypotheses compensate for anomalies not anticipated by the theory in its unmodified form.
Scientists are often skeptical of scientific theories that rely on frequent, unsupported adjustments to sustain them. Ad hoc hypotheses are often characteristic of pseudoscientific subjects such as homeopathy.
Ad hoc in the military
In the military, ad hoc units are created during unpredictable situations, when the cooperation between different units is suddenly needed for fast action.
Ad hoc networking
The term ad hoc networking typically refers to a system of network elements that combine to form a network requiring little or no planning.
- Howard, R. (2002), Smart Mobs: the Next Social Revolution, Perseus
- The dictionary definition of ad hoc at Wiktionary