People have tried to define a state going at least as far back as the days of Plato. In 1933, representatives from a number of countries gathered in Uruguay to define what makes a state, in what became known as the Montevideo Convention. They came up with four defining characteristics that make up a state.

1. A state must have a clearly defined territory. It needs to be clear where that state is geographically. Its territory can have natural borders, like a seacoast, or border the territory of another state.
2. A state must have a permanent population. Antarctica has a clear territory, but since it has no permanent population, it cannot be considered a state.
3. A state must have a functioning government. A state needs to be administered by a governing body with rules and laws that are applicable within the defined border of that state.
4. A state must have the capacity to enter into relations with other states. This essentially means that a state is recognized by other states. In a sense, this is the most crucial characteristic of a state. A territory may meet the other three criteria, but if no one recognizes its legitimacy or existence as a sovereign state, then none of the rest actually matters much in practice.

There are several characteristics of a state. One characteristic is that a state must have defined boundaries with people living within those defined boundaries. Size is not a critical factor as long as the boundaries are defined.

Another important characteristic is the state must be independent. The state will choose its government and conduct its own business. A state is free to make decisions that impact the operation of the state and the lives of the people living in that state. A state doesn’t have to answer to national or international organizations or be limited by other groups. The government of a state often makes many decisions for the state. These include passing laws, making business deals that impact the state, setting educational policy within the state, and determining the punishments for crimes committed within the state.

There are several characteristics of a state.

There are four essential characteristics of a state which include population, territory, sovereignty, and government. Some sources list six or more characteristics when describing a state. Other characteristics may include a food supply, written records, and some type of commerce.

1. Population: A state must have a population which may be variable in size. Populations may or may not share general political beliefs but the ones that do are the most stable. Mobility of the population can affect its political and governmental stability.

2. Territory: States have established territorial boundaries. The size of the territory may change due to the acquisition or secession of land through political negotiations, purchase agreements, or by being overtaken by force such as during a war.

3. Sovereignty: Sovereignty can be considered to be the key characteristic of a state. A state has full and absolute power within its territorial boundaries. States are independent with the power to make and enforce laws, establish foreign policy, and determine the future of its existence within the laws and boundaries.

4. Government: All states have some type of organized government. Government allows the state to establish social order, provide public services, and to make decisions that affect the living conditions of all people living within the territorial boundaries of the state.

A state is characterized by four distinct factors and these are:-

1. A state cannot exist without people. It must have a population regardless of the number of this particular population.
2. A state exists with clearly defined territorial borders. These borders determine the size of the state and the area it can govern.
3. A state must have an established government. This means it should be able to develop laws and have the capacity to enforce the same within its borders. The government should also be recognized by other states globally. 
4. A state must be sovereign. This means it should have the full right to govern itself without interference by external entities.

From the above characteristics a state can be defined as an independent geographical territory with a population governed by established laws.

According to scholars of International Relations, there are two major characteristics of a state.  First, a state has clear borders.  It is an entity that exists in a given geographical space.  Second, and more importantly, the state is sovereign in that area.  Within that geographical space the state (and this implies that the state is synonymous with the government) can do whatever it wants.  The state has no legal responsibility to any higher authority unless it voluntarily enters into treaties creating such obligations.  The state is the only entity with the legal right to commit violence within its boundaries.  This is what it means to be sovereign.

So, a state is a political system that has sovereignty over some defined geographical area.