____ ray (4)

(Other definitions for iota that I've seen before include "Greek equivalent of the letter I" , "Just a jot, from Greek alphabet" , "Tiniest scrap" , "Scintilla" , "very small part" .)

(Other definitions for hint that I've seen before include "signal" , "Tip-off" , "Tip - small amount" , "Indicate indirectly" , "CRT screen coating" .)

(Other definitions for part that I've seen before include "Bit - leave" , "Divide; role" , "Some; break" , "Piece, segment" , "Region" .)

(Other definitions for glow that I've seen before include "Send out light and heat without flame" , "warmth of feeling" , "Incandescence" , "Steady radiance" , "Emit light and heat without flame" .)

(Other definitions for vein that I've seen before include "Seam of mineral" , "Leaf rib; ore layer in rock" , "Vessel carrying blood towards the heart" , "Blood-vessel" , "Distinctive style" .)

(Other definitions for beta that I've seen before include "Second letter of the Greek alphabet" , "It's next after alpha" , "Greek letter -- second in order of importance" , "Old character" , "less than perfect mark" .)