Here is a set of terminologies (not specific to SAP cantext) that you may see frequently in various papers on BPM and SOA.
Web 2.0 -- Actually defining Web 2.0 is a difficult task. But to brief about it, it should be considered as a paradigm shift in the current Web 1.0 (World wide web) technologies. This term was coined by O'Reilly Media in year 2004. Web 2.0 would appear as an enhancement over Web 1.0 with a target to provide more innovative, reliable, secure and faster internet based solutions. Best example would be Wikipedia.
SaaS -- It stands for "Software as a Service". This is one of the modes of software deployment wherein the functionality of an application is hosted as a Service. These services could then be utilized by consumers over the internet. The consumer therefore remains detached from handling of the actual application. SaaS as a fraction of SOA could be used as a part of a widely spread network.
PaaS -- "Platform as a Service" could be considered as development of SaaS. PaaS is more generalized services platform concept. It is not just restricted to specific services as was the case with SaaS. PaaS incorporates handling the design of an entire landscape with a dedicated Service based platform.
Separation of Concerns (SoC) - As the name suggests, it is the process of splitting a complex task into individual functionalities. Earlier it was being implemented by the programming models by modularizing the tasks. The same logic could be compared to an extent while implementing SOA using ESA. The first step towards SOA (the Enterprise Services) also intends to separate some concerned areas with other categories based on which the delegation of tasks could be done.
SOA governance - Organizations earlier had IT governance handling the IT specifically infrastructure. For those opting SOA, the governance is not limited to IT anymore. It has been extended to the business as well incorporating the complete business process lifecycle. The governance includes investing, designing, developing, maintaining and innovate various aspects of SOA. SOA Governance ensures proper adoption of SOA within an organization mitigating the risk factors involved. Once settled with an organized Governance strategy, an organization could mitigate its suspicion about the various unpredictable factors affecting SOA success.
ES Community - SAP ES Community constitutes of SAP, its partners and their widespread industry leader customers. This community would participate in future development of ESA. This community would also be responsible for generating the repository of Enterprise Services.
Consolidation - Literally, it means "merging many things into one". For the business perspective too, the meaning remains the same. But the responsibility increases. Large organizations often require Consolidations of their systems due to expanding businesses, mergers and acquisitions or improving the business processes (implementing BPM moving toward SOA initiatives). SAP NetWeaver incorporates these capabilities using SAP BI (Business Intelligence) and MDM (Master Data Management). NetWeaver also provides BPC (Business Planning and Consolidation) server setup option. Earlier these capabilities were though of the showcase for larger organizations only. But with SAP acquisition of Business Objects, the smaller organizations could also leverage the benefits.
REST Web Services - Until now, whenever we discuss web services, we refer to SOAP based web services. REST stands for Representational state transfer which is software architecture based on resources. Resources are anything which has a URI. REST based communication is using HTTP. The representation of resources could be performed using GET, POST, DELETE or PUT operations. In contrast to the standard RPC methodology of exposing any application as a network object, rest considers each application as a resource. The advantage of using REST is that it utilizes the HTTP and xml as underlying processing technologies which are already widely used.