The meta_key is used to reference a field for a post type, i dont think it will reference the taxonomy of a post type.
Check this out, this may be what you are trying to accomplish:
Related Posts:
- Get term SLUG by term ID
- WordPress taxonomy radio buttons
- Custom taxonomy, get_the_terms, listing in order of parent > child
- Inserting a term into a custom taxonomy
- Custom Taxonomy Archive Page
- Get taxonomy names by post id
- restrict_manage_posts not working in 3.3.1
- Custom taxonomy only shows 0 in autocomplete for terms and “Choose from the most used tags”
- Custom taxonomy on users with UI
- Nice URLs for a Custom Post Type List with a Shared Custom Taxonomy?
- Get terms of posts with category with sql
- Get main parent categories for a product
- Echo Custom Taxonomy Field Values Outside the Loop
- Taxonomy Relationships
- Post slider with custom post type
- Help with a query not working with custom taxonomy
- Filtering more than one term in a taxonomy in WP
- Restricting Users to view only Custom Taxonomies they have entered?
- How to display posts from a single category within a custom taxonomy
- Custom taxonomy parent from another taxonomy
- How to handle “the_terms” inside loop
- How to create drop down for child categories of current taxonomy being viewed?
- How to dynamically add custom taxonomy terms as a sub-menu of an existing menu item, using custom walker class
- Get terms ordered by post date
- Custom Taxonomy list: how to make “choose from most used” default to open, checklist
- custom post type, hide or disable the trash button in publish meta box
- Custom Taxonomy template not showing
- Display hierarchical subterms of custom taxonomy based on depth
- Date archive permalinks for custom taxonomy
- Custom Taxonomies Cababilities
- Get posts from taxonomy URL
- How to implement custom search with input fields?
- Custom taxonomy [year] is directing to yearly archive
- How can I hide admin columns showing extra custom taxonomy fields?
- Manipulate WP Query using a custom post type and multiple tax_query taxonomies
- How to show the a custom taxonomy term on single post metadata
- How to make custom post taxonomy looks like regular categories?
- Create Geographical regions -> countries structure and relationship with taxonomies
- Unexpected results from get_taxonomies() and {$taxonomy}_edit_form and related hook
- Custom Taxonomy Term Archive Page Template that Filters 2 or more Taxonomies
- Custom taxonomy link opens under Posts
- Changing URLs for taxonomies and CPT
- Front-End Custom Taxonomy Tag Select
- Create custom taxonomy and Display in metabox dropdown
- Set tax_query conditionally with new WP_Query
- how to store values in database at hierarchical view
- Strip tags from a the terms() function
- Why can’t I use an array of term slugs in WP_Query?
- Using wp_dropdown_categories in widget options
- Trying to add taxonomy to get_categories() but it’s not working. How to fix this?
- Proper WP conditional tag to check for existing taxonomies to list out terms with wp_list_categories?
- Custom taxonomy archive page requires ?post_type= in url
- Custom taxonomy terms not showing as list Gutenberg Editor WordPress
- Twin value tags as an esoteric taxonomy
- Adding a custom taxonomy to “nav_menu_item”
- Clean Custom URL for Serach + Custom Taxonomy
- Advanced search redirecting to another page then filter further
- Filter through custom taxonomy with an array of taxonomy IDs
- pagination not working on custom-taxonomy template
- Limit Display Number Of Taxonomy Term
- Custom arguments in WP_Query
- Sort and paginate custom post taxonomies alphabetically
- Several taxonomy query (like filter)
- Current taxonomy name (not term!) given a post ID
- Taxonomy Overview Page?
- Search box with field hidden till drop down selection is made
- Can You Build Page Templates Without Extra Files
- How do i make this Taxonomy term code work?
- Unable to get the Parent Custom Taxonomy Terms
- 404 Error on Custom Post Type / Custom Taxonomy
- Unsetting post_tag taxonomy breaks term description for other taxonomies
- Taxonomies on Pages with Custom Formatting
- Catch all taxonomy template
- Is there a way to nest taxonomies or custom fields deeper than one level below the post type?
- Prioritise Pages over Taxonomy Term Root Archive, but not Taxonomy Term Child Archives
- Showing custom taxonomy in woocommerce signle product page
- Main query disturb pre_get_post by category query
- Get custom taxonomy terms that contain posts that have another taxonomy term
- Custom taxonomy not showing in grid view for ‘attachment’ post type
- How To Create Dynamic Permalink To Custom Taxonomy List of Current Posts?
- How to create archive pages for metadata query generated posts (so without taxonomy)?
- How to create a completely functioning separate archive for posts from only 1 or 2 specific categories
- How to get list of custom taxonomies based on custom post type
- how to filter the data’s comparison operators (>= &
- Sort Taxonomy List by Custom Values
- How to filter a taxonomy meta field to the ‘single_term_title’ filter hook
- Using wp_tag_cloud with only current post tag with special class
- Creating a list with multiple categoreis and options
- Custom taxonomy rewrite in permalinks for posts gives 404 on pages
- Query pages by child term
- Custom taxonomy applied to links [duplicate]
- Next/Previous links in custom taxonomy, where item may belong to multiple terms
- Custom Taxonomy registered with multiple custom posts
- Insert term description programmatically into hierarchical custom taxonomy
- Custom Taxonomy + JQuery Tabs
- Get all taxonomy posts by id
- Custom Taxonomy Template Variables Available?
- i need to show featured post on custom taxonomy page
- add_rewrite_rule pagination 404 error on page 4 and above
- Taxonomies starting with a hyphen (minus) to assign B.C. dates to a post