diff -r bf0b6a2c0737 -r c904ec55acae data/dictionary.xml
--- a/data/dictionary.xml	Fri Aug 16 16:16:25 2013 +0200
+++ b/data/dictionary.xml	Fri Aug 16 16:24:56 2013 +0200
@@ -1511,7 +1511,15 @@
 	</concept>
 	<concept>
 		<term abbreviation="OSS" completeForm="open source software" language="en"/>
-		<explanation language="en"><text></text></explanation>
+		<explanation language="en">
+			<text>
+				a category of software similar to Free software;
+				the term „open source software“ was defined by Open Source Initiative;
+				its definition contains ten requirements like free redistribution, available source code or allowing derived works;
+				almost every open source license is also a free software license and vice versa;
+				but there is different philosophical background – the free software movement has user's freedom as the main priority
+			</text>
+		</explanation>
 		<tag>computer</tag>
 	</concept>
 	<concept>