Wikipedia does not currently have an article on "⊶", but our sister project Wiktionary does:

Read the Wiktionary entry on "⊶"

You can also:

• Search for ⊶ in Wikipedia to check for alternative titles or spellings.
• Start the ⊶ article, using the Article Wizard if you wish, or add a request for it; but please remember that Wikipedia is not a dictionary.