In Japanese, the word "shibari" simply translates to "to tie", as you would tie a birthday present, or a bundle of firewood. Kinbaku translates to "tight binding". And both these words also refer to erotic rope bondage, specifically the Japanese style of it. While the roots of shibari are erotic, many practice it as an art form, enjoy the technical side, or value it as non-sexual intimacy.
Rope has a long history in Japan as a tool for restraint. In the Edo period, samurai and officials practiced a martial art called hojojutsu to restrain prisoners. How much this has to do with erotic rope bondage is debated.
What we recognize as modern shibari is a more recent development, emerging through fetish culture and adult magazines in 1950s Japan, with styles and trends changing up to today. The work of Ito Seiu, often called the 'father of modern kinbaku', has been particularly influential, as his photography and art helped shape the aesthetics of rope bondage as we know it.
For those interested in a deeper dive into the history of shibari, we recommend the article The History & Myths of Japanese Bondage by Midori.