Why is Joshua referred to in the Torah as "bin" Nun?

Question:

When the Torah mentions the names of the spies (Numbers 13:4-15), everyone is referred to as "so and so ben (son of) so and so." The only exception is Joshua, who is called Joshua "bin" Nun. Why bin and not ben?

Answer:

In his commentary to Exodus 33:11, Nachmanides (Rabbi Moshe ben Nachman, 1195-1270) points out this unusual vocalization, and suggest that the two words should be read together as "binnun." This name, rooted in the Hebrew word binah, means "the understanding one," and was accorded to Joshua out of respect for his keen intellectual abilities.

Some other explanations that I found:

The Torah tells us that Joshua was Moses' student par excellence. "His attendant, Joshua bin Nun, a lad, would not depart from the tent [of study]" (Exodus 33:11).

We are taught that one's students are considered as his children.1 Some use this idea to explain why Joshua was called "bin" Nun. He may have been Nun's biological child, but he was, to a certain degree, the son of Moses as well. This "dual parentage" is hinted in the unusual way the Torah refers to his relationship with his biological father.

The Chatam Sofer (Rabbi Moses Sofer, 1762-1839), offers another homiletic explanation. The Midrash states (Midrash Rabbah Genesis 47) that when G‑d changed Sarai's name to Sarah (Genesis 17:5), the Hebrew letter yud, which was removed from the name (to be substituted with a hey), felt wronged. Why was it no longer part of the name of this holy woman? G‑d placated the letter by promising to make amends on a future date. This was accomplished when Moses added the letter yud to Joshua's name (Yehoshua), which was originally Hoshea (Numbers 13:16).

In its original state, when it was the final letter of Sarai's name, the yud did not have a vowel -- as is the case with most letters which come at the end of a Hebrew word or name. Now, in order to be the yud which begins the name Joshua it would need the sheva vowel, which is comprised of two dots vertically aligned. These two dots were "borrowed" from the segol vowel which normally is beneath the word "ben," which is three dots set up as a triangle. This leaves only one dot for the word "ben." One dot is the chirik vowel, which changes the pronunciation to "bin."

Best wishes,

Rabbi Baruch S. Davidson