The triangle pointing downward is a female symbol corresponding to the yoni and the upward pointing triangle is the male, the lingam ... When the two triangles are interlaced, it represents the union of the active and passive forces in nature; it represents the male and female elements.
Albert MackeySo important , indeed, is it (Light), and so much does it pervade with its influence the whole Masonic system, that Freemasonry itself anciently received, among other appellations, that of Lux, or Light, to signify that it is to be regarded as that sublime doctrine of Divine Truth by which the path of him who has attained it is to be illuminated in his pilgrimage of life.
Albert Mackey