Sorry to be reviving an old thread but I thought I could clear a few things up that were raised.
Just to point out, Luminaire is used in industry these days as a more technical word for lantern. In other words, a source of light from an electrical base. As Google brings up a few definitions:
# A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.
# The lighting industry uses this term to encompass a "lighting fixture" or "fitting." Luminaires are grouped by mounting type and locations.
Now doesn't this strike a bell. Electrical source of power... providing light. In the Americanized version, Crono's innate element being "Lightning", his most obvious type of magic is his source of "Lightning" element. Moving on Chrono Cross, where Luminaire is an attack based on "chi" or spiritual energy, as the game directly states... This is also supportive of Crono's innate element in the Japanese version, Heavens, which may be interpreted as a source of spirits (but that's not to say there are demonic spirits). So there you have it, Luminaire, an attack based on "chi" related to the "Heavens" that not necessarily means the attack is based on "Lightning"...yet, comes from a source of Lightning element, just like a symbol for its literal definition.
Using the definition of Luminaire, its pretty interesting that both arguments raised in the thread are supported!