Who continued the Persian usage of the term "al-Hind" to describe the region east of the Indus River in ancient times?

Arabs

The Arabs continued the Persian usage of the term "al-Hind" to describe the region east of the Indus River.
The origin of the term "Hindu" can be traced back to an Old Persian word used around the sixth to fifth centuries BCE. This word referred to the geographical region located east of the Indus River, known as Sindhu in Sanskrit. The Arabs adopted this Persian usage and referred to the region as "al-Hind" and its inhabitants as "Hindi." Subsequently, the Turks used the term "Hindu" to describe the people residing east of the Indus River, while they referred to their land as "Hindustan" and their language as "Hindavi." It's important to note that none of these terms initially carried religious connotations; they were primarily geographical and linguistic identifiers. The religious significance of the term "Hindu" developed much later in history.