Astro*Dictionary
by Michael Erlewine

1 article for
"Trimorion"

An aspect in Mundo which embraces three Houses, hence a Mundane square, but which in some instances may actually extend to as much as 120°; hence in Primary Directions it was sometimes called the killing arc, since 120 years were deemed the natural limit of life.

See also:
♦ Aspect ♦ Mundane Aspect ♦ House ♦ Primary Directions