I currently put my hands into WP taxonomy and terms to find solutions for my project. I knew that it's not possible to have same terms slug when creating a term with wp_insert_term in one Custom Taxonomy and between different Custom Taxonomies, but i would like to have different terms linked to the same url (so slugs are involved in it) and get all the related posts to these different terms.

Say a custom Taxonomy 'tax' and the following terms in it :

a (slug : a) 
--b (slug : b)
-c (slug : c)
---d (slug : d)

I can access the different tax term with the following links :


If i want to insert a term with wp_insert_term('e','tax',array(slug=>'a'), WP will modify the slug to 'a1' because slugs should be unique...

So, seems impossible to redirect different terms to the same slug/url and get all the custom posts from 'a' and 'e'.

And what about alias_of argument ? Can't find any full documentation about it . Wasn't it precisely for that kind of issue ? I've inserted several terms with that kind of code : wp_insert_term('e','tax',array(slug=>'e','alias_of'=>'a') but it doesn't change anything, WP creates different unique slugs for all my entries and doesn't care about alias_of.

Is Anybody here can clarify this or have a solution ?

thanks a lot !


Seems to be related to term_group , a feature that isn't really yet supported by WP. There is a term_group field in wp_terms database . The value of this field is set on term creation wp_insert_term($name,$taxonomy,array('alias_of' => $slug) and retrieve when get a term with (for ex get_term_by()->term_group function). There should be a way to query this but with the terms metas support, i don't really see the interest ...

  • 3
    I could only find the alias_of implementation in the wp_insert_term() and wp_update_term() functions so I would think that this is still only half baked featured in the core.
    – birgire
    Dec 15, 2015 at 15:05
  • Yeps, same for me ... but this feature would be interesting because i need a way to display all the posts related to multiple Taxonomy terms on a single url within the same slug... and by the way, make relationships between same term name in different level of the Taxonomy. I could imagine alias_of announce what we will be able to do in future, but when :)
    – Polykrom
    Dec 15, 2015 at 15:17
  • 1
    Maybe this posting, found on the net, could help you a little to enlighten some? I am not sure but it could not harm to read imho. As it seems an interesting item which is not clearly documented.
    – Charles
    Dec 15, 2015 at 15:45
  • @Charles , thanks for the link ... it seems groups and alias aren't supported yet , this post seems to confirm that... Weird.. it looks too that these "on hold" features are in core for years :-/
    – Polykrom
    Dec 15, 2015 at 16:21
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    I just wanted to clarify "I knew that it's not possible to have same terms slug when creating a term with wp_insert_term in one Custom Taxonomy and between different Custom Taxonomies". It is now possible to have the same slug used in multiple taxonomies (as of version 4.2 I believe)
    – Shawn H
    Jan 19, 2016 at 1:49

1 Answer 1


In the Code Reference it says:


(string) Slug of the term to make this term an alias of. Default empty string. Accepts a term slug.

This makes a term an alias of another term. Using your example this is how you would use it:

wp_insert_term( 'e', 'tax', array( 'alias_of' => 'a' ) );

This would create a new term e in the tax taxonomy without its own slug, and posts in e would also show up under the a slug.

  • To clarify this a bit; you're saying http://example.com/tax/e/ and http://example.com/tax/a/ would show the same posts assigned to category e?
    – Howdy_McGee
    Feb 16, 2016 at 19:31
  • 2
    No, in my example, http://example.com/tax/e/ would not exist, as the term e would not have been assigned a slug. All posts using e would show up in http://example.com/tax/a/. Feb 16, 2016 at 19:35

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