diff --git a/src/common-principles.md b/src/common-principles.md
index 0bd9b5891c..1e6eab8424 100644
--- a/src/common-principles.md
+++ b/src/common-principles.md
@@ -564,7 +564,7 @@ like in the example below.
 
 Large tabular information, such as physiological recordings, MUST be stored with
 [compressed tab-delineated (TSVGZ) files](glossary.md#tsvgz-extensions) when
-so established by the specifications.
+so established by the specification.
 Rules for formatting plain-text tabular files apply to TSVGZ files with three exceptions:
 
 1.  The contents of TSVGZ files MUST be compressed with