External reference – SEO WIKI
External links are inbound or outbound. The first option is when the link on the external site leads to your resource, the second – if your resource, on the contrary, refers to some external web page.
Speaking of external links, it is advisable to clarify which type is in question. The expression “outbound external link” is incorrect; instead, you should simply say “outbound link”. Incoming links are recommended to be called reverse for greater correctness.