What’s the difference between term_id and term_taxonomy_id

The title says it all. At the moment in my custom taxonomies I’m getting the terms using the term id and taxonomy name.

Thought this question would’ve been asked before but can’t find it anywhere! So just thought I’d ask and see if anyone has any answers.

If you take a look into the WordPress documentation you will find WordPress Taxonomies

• term_id is the ID of a term in the terms table
• term_taxonomy_id is a unique ID for the term + taxonomy pair.