A theory of value is a theory about what things in the world are good, desirable, and important. Such theories aim at answering a practical rather than a purely theoretical question since to conclude that a state of affairs is good is to have a reason for acting so as to bring it about or, if it exists already, to maintain it.
For the teleologist actions are right if and only if they are means to some admitted non-moral good whereas for the deontologist they are valuable in themselves. In more general terms this is the question of whether or not morality requires an external jsutification.
X has extrinsic value if it is a means to, or in some way contributes to Y. Y has intrinsic value if it is good, worth pursuing in itself, without reference to some other entity.... Hence a theory of value must propose some things that are good in themselves...
(Antony Flew: A Dictionary of Philosophy, St. Martin's Press 1979)

1. The quality or property of a thing that makes it useful, desired or esteemed (pragmatic aspect).
2. An abstract and general principle concerning the patterns of behavior within a particular culture or society, which, through the process of socialization, the members of that society hold in high regard. These social values form central principles around which individual and societal goals can become integrated (e.g. freedom, justice).
(Arthur S. Reber: Dictionary of Psychology, Penguin 1985)

1. Generally and loosely, conscious, voluntary selection of particular action or choice from many potential actions or choices.
2. In the writings of the early introspectionists, a complex arrangement of kinesthetic sensations and Content/images that occurred along with a conceptualized goal or end of one's actions or thoughts.
(Arthur S. Reber: Dictionary of Psychology, Penguin 1985)

The faculty of the will; or an item conceived as the product of such a faculty. In many dualist and empiricist accounts of action, volitions are mental items that cause bodily motions on occasions of human agency. In recent philosophy, volitions are introduced in various roles, sometimes as a species of intention.
(Ted Honderich: The Oxford Companion to Philosophy, Oxford University Press 1995)

Wille (gr. boulesis, lat. voluntas), die menschliche Fähigkeit, sich auf Grund von Motiven und in bewusster Stellungnahme zu ihnen für Handlungen zu entscheiden, im Unterschied zu Trieb, Instinkt und Begehren. Zu einem vollständigen Willensvorgang gehören also
1. das Motiv oder der Beweggrund, der in einer Gemütsbewegung, einer Zweckvorstellung oder in dem Ergebnis einer Überlegung über eine zu treffende Wahl bestehen kann.
2. das eigentliche Wollen, der Willensakt oder Entschluss.
3. die Willenshandlung, die Verwirklichung des Gewollten, die eine innere oder eine äussere Tat sein kann.
(J. Hoffmeister: Wörterbuch der Philosophischen Begriffe, Meiner Verlag, 1955)