[PATCH] More missing terms in glossary.txt

Describe a DAG and octopus, and change wording of tree object.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/glossary.txt

@@ -27,14 +27,20 @@ blob object::
 
 tree object::
 	An object containing a list of file names and modes along with refs
-	to the associated blob and/or tree objects. A tree object is
+	to the associated blob and/or tree objects. A tree is equivalent
-	equivalent to a directory.
+	to a directory.
 
 tree::
 	Either a working tree, or a tree object together with the
 	dependent blob and tree objects (i.e. a stored representation
 	of a working tree).
 
+DAG::
+	Directed acyclic graph. The commit objects form a directed acyclic
+	graph, because they have parents (directed), and the graph of commit
+	objects is acyclic (there is no chain which begins and ends with the
+	same object).
+
 index::
 	A collection of files with stat information, whose contents are
 	stored as objects. The cache is a stored version of your working
@@ -142,6 +148,10 @@ merge::
 	merge uses heuristics to accomplish that. Evidently, an automatic
 	merge can fail.
 
+octopus::
+	To merge more than two branches. Also denotes an intelligent
+	predator.
+
 resolve::
 	The action of fixing up manually what a failed automatic merge
 	left behind.