The Hebrew word "tehillim" (תְּהִלִּים) is the title of the biblical Book of Psalms. It means "praises" or "songs of praise." Not all of the 150 psalms are praise poems; many are laments, confessions, or cries for help. But the overall collection is categorized under the umbrella of praise, which is why the Hebrew title stuck.
The Hebrew word "tehillim" (תְּהִלִּים) is the title of the biblical Book of Psalms. It means "praises" or "songs of praise." Not all of the 150 psalms are praise poems; many are laments, confessions, or cries for help. But the overall collection is categorized under the umbrella of praise, which is why the Hebrew title stuck.