1.
growing wider toward the end; fan shape
A shape that broadens out toward its far end, like an opened folding fan. Used both literally and as an auspicious image of expanding fortune over time.
Compound of 末 (end, far future) + 広がる (to spread, widen). Literally "widening toward the end."
Cultural note
The shape evokes the folding fan (扇子), which is itself considered an auspicious object. The number 8 (八) is called 末広がり because the kanji 八 widens at the bottom, making it a lucky number associated with growing prosperity.