I don't think there is such a beast as "enterprise software". I do, however, think that there is such a thing as an "enterprise resource". If you look at the items you described (water, power, connectivity, information), the common theme is that there is a resource that is used. The mechanism by which that resource is distributed isn't the important factor.

Taking connectivity as an example, you can provide that resource using CAT-5, twisted-pair, wireless, optical ... the list goes on and on. In fact, connectivity is often provided over a combination of those methods. So, which connectivity method is "enterprise-level"? Well, it depends on what the enterprise requires. Many enterprises wouldn't consider twisted-pair to be "enterprise-level," because it isn't powerful enough. But, many other enterprises use it quite nicely.

I think the same goes for programming languages, only moreso. Programming languages don't actually distribute or store an enterprise resource. They provide the foundation for creating the tool(s) that distribute or store said resource. Oracle is an enterprise-level application because it can store and search information with the requirements an enterprise has concerning said information. One would need to speak about an application written in Perl that meets the need of information distribution. For example, no-one would deny that Amazon or CitySearch are "enterprises." They both use Perl, which means that Perl can be used as a foundation for building applications that can store and/or distribute enterprise resources.

In that regard, every single programming language in common use^* can be used to build an application that handles an enterprise resource. One now has to discuss the costs and benefits associated with writing a given application in a given programming language. For example, when writing a web application, no-one seriously thinks that C is the appropriate way to go. Yet, C is the only language used to write the webserver or an enterprise-capable RDBMS. That's the same calculus, by the way, that's used to evaluate MySQL vs. SQL*Server vs. Oracle. There's no reason it shouldn't be applied to programming languages in the same fashion.

*: Befunge and Brainf*ck need not apply.