The WordPress core doesn’t know about keywords and doesn’t have any features related to keywords.
However, keywords related features (fields or else) are sometimes added by themes and plugins. WP/LR Sync also has a feature to do this. It’s important to understand how those keywords are implemented by your WordPress install if they are available.
The Keywords Taxonomy
Usually, the keywords are added as a WordPress taxonomy and used by the Media Library. “Keywords” is actually the friendly name of the taxonomy. The internal name is probably quite different.
In the case of WP/LR Sync, the Keyword feature (added through an option in the settings) is called attachment_keyword. If keywords were added by your theme, or by another plugin, the internal name is probably different and therefore, it’s like you are dealing with two totally different taxonomies, even though the friendly name is the same.
Enable Keywords & Sync Keywords
In WP/LR Sync settings, there are two important options: Enable Keywords and Sync Keywords.
The first one will create the Keywords taxonomy (attachment_keyword) we talked about earlier.
The second option will let you pick this new taxonomy, or another taxonomy (if you would like to use the Keywords taxonomy created by the theme or another plugin for example). With that setting, WP/LR Sync will keep the keywords updated between Lightroom and this taxonomy.
Resync with Extensions
WP/LR Sync also keeps the information about your keywords in its own database, in WordPress. Even if you are not using any Keywords taxonomy yet, the keywords are kept in this database. You can have a look at the content of this database by visiting the Collections & Keywords screen.
Then, the day you start using an extension that is using keywords, or if you start using the Keywords taxonomy we discussed, you can click on the Resync with Extensions button in the Extensions screen. WP/LR Sync will generate events for everything that happened between Lightroom and WordPress, basically asking the extensions and the Sync Keywords feature to do their job :)
If you have any questions related to keywords, please add a comment below :)