Profit - In economics, the term profit has two related but distinct meanings. Normal profit represents the total opportunity costs (both explicit and implicit) of a venture to an entrepreneur or investor. Whilst economic profit (is, the difference between a firm's total revenue and all costs, including normal profit. (Perkin, 1997) and http://en.wikipedia.org/wiki/Profit_(economics)

Market - A market is any one of a variety of systems, institutions, procedures, social relations and infrastructures whereby businesses sell their goods, services and labour to people in exchange for money.
(Perkin, 1997) and  http://en.wikipedia.org/wiki/Market

Opportunity Cost - Opportunity cost is the cost related to the next-best choice available to someone who has picked among several mutually exclusive choices. It is a key concept in economics. It has been described as expressing "the basic relationship between scarcity and choice." The notion of opportunity cost plays a crucial part in ensuring that scarce resources are used efficiently.
(Perkin, 1997) and http://en.wikipedia.org/wiki/Opportunity_cost

Production Possibility Curve (PPC) - In economics a production-possibility curve or product transformation curve, is a graph that shows the different rates of production of two goods and/or services that an economy or individual can produce efficiently during a specified period of time with a limited quantity of productive resources, or factors of production. The PPC shows the maximum amount of one commodity that can be obtained for any specified production level of the other commodity, given the society's technology and the number of factors of production available.
(Perkin, 1997) and http://en.wikipedia.org/wiki/Production_Possibility_Curve