al-Salāmu ‘alaykum wa rahmatullāh,
One of the most fascinating aspects of Arabic in my eyes, is finding the relationship between words that come from the same root but do not seem to have an obvious link in their meaning. The study of etymology in any language is fascinating in itself, but due to the root system in Arabic the findings are more likely to be linked to Arabic itself rather than finding that they are loan words from another language, as is often the case with English etymology, for example.
One such word that I came across was the word jaa'izah جائزة meaning 'a gift'. The root of this word is jeem-waw-zay ج – و – ز. Ibn Faaris mentions in Mu'jam Maqaayees al-Lughah that this root has two original meanings; one is related to passing through/traversing/crossing, as in Yunus, verse 90:
وَجَاوَزْنَا بِبَنِي إِسْرَائِيلَ الْبَحْرَ
And We took the Children of Israel across the sea
and the other is the 'middle' of something (the jawz جَوْز of a thing is its middle).
So what, then, is the relationship between the meaning of a gift, and the original root meanings?
In this regard, Ibn Durayd mentioned in Jamharat al-Lughah that the word jaa'izah developed the meaning of 'gift' when a commander once took his army to meet the opposing force, but found a river laying between his men and the enemy. So he said to his troops,
من جاز هذا النهر فله كذا وكذا
Whoever crosses (jaaza) this river will receive such-and-such a thing [as a gift]
So whenever a man would reach the other side, he would receive a jaa'izah – or, a [token of] something that has crossed over'.
And Allaah knows best.