This is the 578th most frequent Icelandic word.
leiðinni
"Leiðinni" means "on the way" in English.
In this sentence, 'leiðinni' refers to being in the process of traveling or reaching a destination.
Ég er á leiðinni í skólann.
I am on the way to school.
Here, 'leiðinni' describes the state of motion towards a destination.
Bíllinn var á leiðinni þegar hann bilaði.
The car was on its way when it broke down.
In this usage, 'leiðinni' indicates a point in a journey, specifically the route home.