Each row in the wp_term_taxonomy table represents the dyad of a term slug and a taxonomy – say, the tag slug ‘mint’ and the taxonomy ‘herb’. Historically, terms in different taxonomies that shared the same slug would share a single row in the wp_terms table; thus, the ‘mint’ row in wp_terms could correspond to a term-taxonomy pair in the ‘government_building’ taxonomy as well as ‘herb’