What is "ashrei"

The Ashrei (Hebrew: אַשְׁרֵי יוֹשְׁבֵי בֵיתֶךָ, עוֹד יְהַלְלוּךָ סֶּלָה, Ashrei yoshvei veitecha, od y’hallelucha, selah!; English: Happy are they who dwell in Your house; they will praise You, always!) is a prayer that is recited at least three times daily in Jewish prayers, twice during Shacharit and once during Mincha. The prayer is composed primarily of Psalm 145 in its entirety, with a verse each from Psalms 84 and 144 added to the beginning, and a verse from Psalm 115 added to the end. The first two verses that are added both start with the Hebrew word "ashrei" (translating to "happy" or "praiseworthy" or "fortunate"), hence the prayer's name.