As Bertrand Russell once wrote, power is the fundamental term in political philosophy and social sciences . However, despite (or perhaps due to) its importance and vast use, the literature on power is an amalgamate of widely diversified views, understandings, categorisations, and typologies of the term. Moreover, we can find a long list of vocabularies in the political texts with relevant, similar or identical meaning to power: influence, control, pouvoir, puissance, Macht, Herrschaft, Gewalt, imperium, potestas, auctoritas, potentia .
According to Hanna Pitkin, power is etymologically connected to pouvoir in French and potestas in Latin . In Latin, there is also the term potentia, with a relevant but subtly different meaning. Spinoza differentiates potestas, as being in the power of another, from potentia, which can mean being in the power to do things . This, as I will demonstrate later in the article, is, in fact, the main point of differentiation between two major senses of power.
In the following sections, I will first recount the major understandings of the term, including power-over, power-to and power-with. This is followed by a brief review of the major reasons for this diversion in the definition of power. I will conclude by discussing how we can have a single, comprehensive understanding of the term.
The Understandings of power
The majority of the references, which discuss power, divide the understandings of the term into two categories, namely power-to and power-over. However, Amy Allen, in Rethinking Power , adds a third category to the two, which is power-with. The third category, however, does not seem to be as significant as the other two. Nonetheless, in the following, I will explain all the three understandings in more detail.
This notion of power refers to the understanding that power is the ability of one agent to make another agent do what s/he would not normally do. Robert A. Dahl’s “intuitive idea of power” is a classic example of this sense of power: “A has power over B to the extent that he can get B to do something that B would not otherwise do” . According to Dahl, in this sense, there is a possible identity of “power” with “cause”.
Examples of this understanding of power are:
Amy Allen: “the ability of an actor or set of actors to constrain the choices available to another actor or set of actors in a nontrivial way.” 
Max Weber: “the probability that one actor within a social relationship will be in a position to carry out his own will despite resistance…” 
Lukes “A exercises power over B when A affects B in a manner contrary to B’s interests” .
Michel Foucault: “if we speak of the structures or the mechanisms of power, it is only insofar as we suppose that certain persons exercise power over others” .
An important case of power-over is domination. However, domination is a particular type of the restrictive and exploitative side of this understanding of power. There are other types, which are more productive. Examples of the productive end of power-over spectrum are the powers of a parent, a coach or a music conductor.
Another important point according to Allen is that this sense of power should not be limited to the cases with explicit or conscious strategies or intentions. It can be “held or exercised “in routine or unconsidered ways” by people who do not necessarily deliberately intend to do so .
A significant portion of the references, however, use power as the ability to act. In this sense, power is essentially viewed as power-to. Peter Morriss in Power: A Philosophical Analysis  argues that our primary understanding of power is as power-to. According to him, “‘power’ is best thought of as the ability to effect outcomes, not the ability to affect others” .
Examples of power-to in the literature:
Thomas Hobbes “The power of a Man, (to take it Universally,) is his present means, to obtain some future apparent Good” 
Hannah Arendt: “the human ability not just to act but to act in concert” .
Allen: “the ability of an individual actor to attain an end or series of ends” .
Allen links this sense of power to the feminists’ empowerment theory. She understands resistance as a particular form of power-to and defines it as the ability of an individual actor to attain an end or series of ends that serve to subvert domination .
Allen, in Rethinking Power, adds another category to the two above, which seems to be deliberately defined for the feminist studies. She names this category “power-with” and defines it as the ability of a collectivity to act together for the attainment of a common or shared end or series of ends.
Examples of this sense of power are:
Allen: “the ability of a collectivity to act together for the shared or common purpose of overturning a system of domination” .
Hannah Arendt: “the human ability not just to act but to act in concert” .
This third category, however, does not seem to be as significant as the other two. This is perhaps why even Allen does not use it in her later publications.
On the diversity of understandings
Two reasons for the diversity of the understandings of the term “power” are the most evident. First, authors use senses of the term that are closer or more pertinent to the sociological, philosophical or political aim of their studies. Second, our understanding of power is itself under the influence of power.
Another issue regarding the diversity is the significance of the distinction. A range of scholars such as Pitkin , Wartenberg  argue that the senses of power are in fact distinct and each refers to a separate concept. However, I side with the other group, such as Allen  and Lukes , who regard various understandings as fundamentally the same.
According to the second group, power-to is the most comprehensive sense of the term. The other two categories can be redefined as power-to. By this approach, power-over is, thus, one actor’s power to make the other actor act in a certain way and power-with (if we even consider this sense as a major one) can be defined as a collectivity’s power to act together for the attainment of a common or shared end or series of ends.
Therefore, to have a comprehensive definition which can include all the senses, we can use Allen’s definition of power, simply as:
“the ability or capacity of an actor or set of actors to act” .
1. Russell, B., Power: A new social analysis. 1938.
2. Dahl, R.A., The concept of power. Behavioral science, 1957. 2(3): p. 201-215.
3. Allen, A., Feminist Perspectives on Power, in The Stanford Encyclopedia of Philosophy, E.N. Zalta, Editor. 2016.
4. Morriss, P., Steven Lukes on the concept of power. Political Studies Review, 2006. 4(2): p. 124-135.
5. Allen, A., Rethinking power. Hypatia, 1998. 13(1): p. 21-40.
6. Weber, M., Economy and society: An outline of interpretive sociology. 1978: Univ of California Press.
7. Steven, L., Power: A radical view. London and New York: Macmillan, 1974.
8. Dreyfus, H.L., Michel Foucault, Beyond Structuralism and Hermeneutics. 1983.
9. Morriss, P., Power: a philosophical analysis. 2002: Manchester University Press.
10. Hobbes, T. and R. Tuck, Hobbes: Leviathan: Revised student edition. 1996: Cambridge University Press.
11. Arendt, H., On Violence New York. Brace and World: Hartcourt, 1969.
12. Pitkin, H.F., Wittgenstein and Justice: On the Significance of Ludwig Wittgenstein for Social and Political Thought. 1974.
13. Wartenberg, T.E., The forms of power: From domination to transformation. 1990: Temple University Press.
14. Allen, A., The power of feminist theory: Domination, resistance, solidarity. 1999.
15. Lukes, S., Power: A Radical View (2nd). Hampshire: Palgrave Macmillan, 2005.