The wind instrument sounded during Rosh Hashanah services is the shofar.
A shofar is a ritual horn, most commonly made from a ram’s horn. Unlike a modern trumpet, it has no valves or keys; the player produces its tones by controlling the lips, breath, and embouchure. Its irregular natural shape gives the sound a distinctive, raw character.
The shofar’s Rosh Hashanah role is rooted in biblical descriptions of the first day of Tishrei as a day of horn-blowing or remembrance. Its blasts are linked with themes of kingship, remembrance, repentance, and spiritual awakening. The principal traditional sounds include tekiah, shevarim, and teruah.
Trumpets are mentioned separately in biblical ritual, so they are not the canonical answer here. The shofar is also heard during Elul in many communities and at the conclusion of Yom Kippur.