diff --git a/docs/glossary.rst b/docs/glossary.rst
index 20ad21c..8bb35bc 100644
--- a/docs/glossary.rst
+++ b/docs/glossary.rst
@@ -36,6 +36,9 @@
    CSS
       Compute Sub-System
 
+   CRB
+      Command Response Buffer
+
    CVE
       Common Vulnerabilities and Exposures. A CVE document is commonly used to
       describe a publicly-known security vulnerability.
@@ -88,6 +91,9 @@
    FF-A
       Firmware Framework for Arm A-profile
 
+   FIFO
+      First In, First Out
+
    FIP
       Firmware Image Package
 
@@ -103,6 +109,9 @@
    HES
       Arm CCA Hardware Enforced Security
 
+   I2C
+      Inter-Integrated Circuit Protocol
+
    ISA
       Instruction Set Architecture
 
@@ -211,6 +220,9 @@
    SPM
       Secure Partition Manager
 
+   SPI
+      Serial Peripheral Interface
+
    SRTM
       Static Root of Trust for Measurement