diff --git a/zsh-completions-howto.org b/zsh-completions-howto.org
index 5a71570..41bcac5 100644
--- a/zsh-completions-howto.org
+++ b/zsh-completions-howto.org
@@ -194,6 +194,18 @@ For example:
 _arguments '-f[input file]:filename:_files' 
 #+END_SRC
 
+| -OPT                  | single option                                                                                                                                    |
+| +OPT                  | single option beginning with +                                                                                                                   |
+| -+OPT                 | single option beginning with + or -                                                                                                              |
+| +-OPT                 | single option beginning with + or -                                                                                                              |
+| {-OPT1,--OPT2}        | list of alternatives for an option (e.g. short & long forms). This is not a different specification but a trick that relies on braces expansion. |
+| -OPT-                 | indicates the argument of the option must come directly after the option name, e.g. -optARG                                                      |
+| -OPT+                 | indicates the argument of the option may come directly after the option or as a separate word, e.g. -optARG or -opt ARG                          |
+| -OPT=                 | indicates the argument of the option may come as a separate word, or separated from the option with an = sign, e.g. -opt=ARG or -opt ARG         |
+| -OPT=-                | indicates the argument of the option must appear after an = sign, not as a separate word                                                         |
+| OPTSPEC[explanation]  | the explanation string will be displayed along with the option (OPTSPEC is any of the previously mentioned option specifications)                |
+| *OPTSPEC              | indicates that the option may be repeated (OPTSPEC is any of the previously mentioned option specifications)                                     |
+| OPTSPEC:ARG1:ARG2:etc | for specifying options that take arguments (see below for option argument specification)                                                         |