'Energy' - is it an adjective or noun?

[Nickelodeon]

Energy is a value expressed in terms of calories, joules, BTUs so in this sense I would have thought it is an adjective describing a system's energy potential. However, confusion arises because it is also a noun as in 'The world is running out of energy'.
Is it both? or maybe it isn't an adjective but someother grammatical term.

 

[vanesch]

Energy is a value expressed in terms of calories, joules, BTUs so in this sense I would have thought it is an adjective describing a system's energy potential. However, confusion arises because it is also a noun as in 'The world is running out of energy'.
Is it both? or maybe it isn't an adjective but someother grammatical term.

This is not really physics but rather english grammar.

I'm not a native English speaker, but I'm pretty sure that the word "energy" is a noun. The adjective would be rather "energetic" and the adverb, "energetically", no ?

http://www.wordreference.com/definition/energy
http://www.wordreference.com/definition/energetic
http://www.wordreference.com/definition/energetically

 

[Stonebridge]

The word "energy" is a noun. The adjective would be "energetic".
Grammatically that's all there is to it.
In physics it is a quantity that has meaning and can be measured; just like force, velocity, mass etc etc. As such it can give you important information about a system. That doesn't make it an adjective from a grammatical point of view.
We would talk about "the energy of a system", "the colour of a shirt".
Colour is a noun. If the colour of the shirt is red. Red is an adjective.
Hope this helps.

 

[Nickelodeon]

The word "energy" is a noun. The adjective would be "energetic".
Grammatically that's all there is to it.
In physics it is a quantity that has meaning and can be measured; just like force, velocity, mass etc etc. As such it can give you important information about a system. That doesn't make it an adjective from a grammatical point of view.
We would talk about "the energy of a system", "the colour of a shirt".
Colour is a noun. If the colour of the shirt is red. Red is an adjective.
Hope this helps.

I think it helps but in 'we have an energy crisis' I think the noun in this case is crisis and the adjective is energy (describing what kind of crisis).

 

[Stonebridge]

I think it helps but in 'we have an energy crisis' I think the noun in this case is crisis and the adjective is energy (describing what kind of crisis).

This usage is commonly referred to as a noun-adjective. Energy crisis can be expressed as "a crisis of energy" or "a crisis in energy", where energy, there, is a noun.
Other examples: government department, nursery school. These also involve noun-adjectives where an alternative is not really possible.
(Sorry mods: we seem to be a bit off topic!)

 

[vanesch]

Moved this to general discussion, as this is about english grammar.