Fr.: aigrette de diffraction
One of several light rays emanating from a bright light source in images taken with → reflecting telescopes. They are artifacts caused by light diffracting around the support or → spider vanes of the → secondary mirror.
M.E. spik(e) from O.N. spikr "nail;" akin to M.L.G. spiker "nail."
Sixak, from six "spur, spit; thorn; any pointed thing," + -ak a suffix of similarity and nuance.
Fr.: pointe thermale