1.
abyss, the depths, bottomless pit
A deep, dark place or the lowest possible state. Used figuratively for situations of extreme despair, ruin, or downfall.
2.
below the stage, trap cellar (theater)
In traditional Japanese theater (kabuki), the space beneath the stage used for special effects, disappearances, and scene changes.
奈落 originally comes from the Sanskrit word "naraka" meaning hell, borrowed into Japanese through Buddhist texts.
SENSE 1 — ABYSS:
Almost always used in the expression 奈落の底 (the bottom of the abyss). Describes extreme despair, ruin, or a disastrous fall from grace.
SENSE 2 — THEATER:
In kabuki and other traditional theater, the space beneath the stage. Actors and set pieces can be raised or lowered through trapdoors.
Etymology
From Sanskrit "naraka" (hell) via Buddhist terminology. The kanji are ateji (phonetic characters chosen for their readings, not meanings).