The easiest way to illustrate the difference between a state and a province is to compare the governmental authority and geographical organization of two countries, one with each type of system. For purposes of this comparison, we will use China as our example of a province structure and the United States of America as our example of a state structure. It is important to note that states and provinces in each country are not the same. There can be significant differences between state structures in two countries. Their level of authority and function in relation to the federal government can vary significantly. It is therefore best to understand these systems in the context of the country in which they exist.
Small geographic divisions like provinces and states derive many of their rights and laws from the central or federal government that operates for the benefit of all citizens across the country. However, one minor difference we find is that provinces in China retain much more control over their internal matters than do the states in the USA system. Aside from Taiwan, which is a special case, the remaining provinces may very well take into consideration much of what the central government wants done, but can also reject it. The real power comes from the Central Committee, to which the governor of every province must be accountable, rather than to the federal government. It should be noted that there tends to be more appointments in this particular form of organization in China and less in the way of elected officials.
When it comes to lawmaking, states in the USA do not have the option of passing and enforcing legislation that contradicts federal laws. When a state law is understood by some to be in direct conflict with federal law, due process through a judicial system allows for the matter to be reviewed and the state law rendered null and void if it is judged to be in conflict with federal law. This does not happen often, since so many of the persons who represent the interests of each state at the federal level are elected and are expected to be actively engaged in the formulation of federal laws that does not compromise the well-being of any state.
Again, the exact relationship of a province or a state to its federal or central government would vary in form and structure from one country to another. For example, what is true of provinces in China are not necessarily true of provinces in Canada. Depending on the countries compared, there may be no differences between state organization and province structure at all.