diff --git a/source/about/terminology.rst b/source/about/terminology.rst
new file mode 100644
index 00000000..285e20bd
--- /dev/null
+++ b/source/about/terminology.rst
@@ -0,0 +1,45 @@
+.. _doc_about_terminology:
+
+Introduction
+============
+
+Throughout this documentation you will find references to standards, specific
+terminology, and various implementation choices. This page is meant to introduce
+you to some of the specifics of RPKI.
+
+ROAs, VRPs and ROV
+------------------
+
+It's quite common to use the term ROA and VRP interchangeably, but they are quite
+different.
+
+Route Origin Attestations (ROAs) are cryptographically signed objects that
+contain a statement authorising a *single* Autonomous System Number (ASN) to
+originate one or more IP prefixes, along with their maximum prefix length. A ROA
+can only be created by the legitimate holder of the IP prefixes contained within
+it.
+
+RPKI Relying Party software performs cryptographic verification on all published
+ROAs. If everything checks out, the software will produce one or more validated
+ROA payloads (VRPs) for each ROA, depending on how many IP prefixes are
+contained with in it. Each VRP is a tuple of an ASN, a single prefix and its
+maximum prefix length. If verification fails, the ROA is discarded and it'll be
+like no statement was ever made.
+
+The collection of all VRPs can be compared to the BGP route announcements seen
+by your routers. This process is called Route Origin Validation (ROV).
+
+Verification, Validation and Validity
+-------------------------------------
+
+The terms "Valid" and "Invalid" are often used in different contexts, which can
+be confusing.
+
+As explained, ROAs and all related crytographic objects are verified by Relying
+Party Software. If they pass verification, one or more VRPs are emitted and each
+is compared to a BGP route. If the route origin is authorised by the VRP, it is
+considered "RPKI Valid", if it isn't it is "RPKI Invalid". If nothing can be
+said about the validity of the route, it is considered "RPKI NotFound".
+
+Only a ROA that has passed cryptographic verification – i.e. a *Validated ROA* –
+can make a BGP route "RPKI Valid" or "RPKI Invalid".
diff --git a/source/index.rst b/source/index.rst
index 32be8e25..3fc40c2c 100644
--- a/source/index.rst
+++ b/source/index.rst
@@ -39,6 +39,7 @@ The main documentation is organised into the following sections:
about/introduction
about/faq
+ about/terminology
about/help
.. toctree::
diff --git a/source/ops/router-support.rst b/source/ops/router-support.rst
index fbae1c4d..20d79479 100644
--- a/source/ops/router-support.rst
+++ b/source/ops/router-support.rst
@@ -61,7 +61,7 @@ RTRLib is a C library that implements the client side of the RPKI-RTR
protocol, as well as route origin validation. RTRlib powers RPKI in BGP software
routers such as `FRR `_. In a nutshell, it maintains
data from RPKI relying party software and allows to verify whether an autonomous
-system (AS) is the legitimate origin AS, based on the fetched valid ROA data.
+system (AS) is the legitimate origin AS, based on the fetched validated ROA data.
`BGP‑SRx
`_
by NIST is a prototype that can perform similar functions.