It is sounded to interrupt.
A shofar is a ritual horn
Britannica defines the shofar as a ritual musical instrument made from the horn of a ram or other animal and used on important Jewish public and religious occasions.
This is one of the oldest sound signals in Jewish ritual life.
Its most important modern role is on Rosh Hashanah
Britannica says the shofar's most important modern use is on Rosh Hashanah, when it is sounded in synagogue to call the Jewish people to spiritual reawakening. It is also sounded on Yom Kippur as a call to repentance and sacrifice.
That gets the point right. The shofar is not background sound. It is a summons.
The instrument carries memory and urgency
Britannica notes that in biblical times the shofar announced the Sabbath, the New Moon, and the anointing of kings.
That long history is part of why the sound still lands. It compresses authority, alarm, ritual time, and collective memory into one blast.
Why it still matters
The shofar still matters because Judaism does not rely only on explanation. Some truths have to be heard as a rupture in routine.
The shortest accurate answer
A shofar is a ritual horn used in Jewish life, most prominently on Rosh Hashanah and Yom Kippur, as a call to spiritual awakening and repentance.