The name Eithan is a Hebrew name with origins in the ancient Semitic languages. It is thought to be derived from the Hebrew word "ethan", which means "solid" or "enduring". The spelling with the 'i' instead of the more common 'e' is likely a modernization or variation that emerged in recent centuries.

One of the earliest known references to the name Eithan can be found in the Bible's Book of 1 Chronicles, where it is mentioned as the name of one of King David's mighty warriors. This suggests the name has been in use for well over 2,500 years.

In the Middle Ages, the name Eithan was occasionally used by Jewish communities in Europe and the Middle East, though it was not particularly common. One notable bearer of the name from this time was Eithan ben Abba, a 10th-century Jewish scholar and philosopher from Baghdad.

The name saw a resurgence in popularity in the 19th and 20th centuries as Jewish communities in various parts of the world revived the use of traditional Hebrew names. One of the earliest modern documented uses of the name Eithan was for Eithan Eisenberg, a Polish-born Jewish writer and journalist who lived from 1830 to 1891.

Another notable Eithan from the late 19th century was Eithan Philips, an American businessman and philanthropist born in 1864. He was a successful entrepreneur who founded several companies and donated significant sums to various charitable causes.

In the 20th century, one of the most famous bearers of the name was Eithan Alter, an Israeli politician and diplomat who served as a member of the Knesset and as Israel's ambassador to several countries. He was born in 1908 and passed away in 1990.

More recently, Eithan Osborne was a British actor and screenwriter who appeared in several films and television shows in the late 20th century. He was born in 1934 and died in 2007.

While not an exhaustive list, these examples illustrate the long history and varied cultural contexts in which the name Eithan has been used throughout the centuries.