German LICHTERLOH

German LICHTERLOH is a (sort of) compound adverb meaning (burning) "with a bright flame". I came across this word through Andrew Hammel's Word of the Week  in his blog German Joys . Its etymology is worth a glance:
The element LICHT(er) is a genitive form of "licht" meaning "bright, light", derived from Proto-Indo-European *LEUK- "shine", as to be found in Latin LUX or Vedic ("Sanskrit") ROCATE (with the l having changed into r) "shines", the root is also there in Greek LEUKOS "white".
Now we get to the second element -LOH:
LOHE means "flame" (LOUG in Old High German) which is derived from the above mentioned root *LEUK "shine".
So, we find that the two components of LICHTERLOH are both derived from the same Indo-European root, *LEUK.
Moreover, there is a quite similar word, now to be found only in place names:
LOH (like in Güterloh, Oslo), in Old High German meaning "grove", "clearing". Connected with Vedic LOKA "free space, world" and Latin LUCUS "grove", it is derived from the Proto-Indo-European noun *LOUKO which belongs to our root *LEUK- "shine".
So we can see an etymological connection between two quite different semantic fields:
one with the meaning "shine" in its centre (connected with "bright", "fire", "burning", "(blazing) white"), and an altogether different lexical branch with the core meaning "free space", "clearing", "grove" (the German word for grove is LICHTUNG showing a similar connection between a (supposedly) "cleared piece of land" and words tied to "shine, be bright".
The link between the two concepts is, presumably, the notion that a clearing is a place where the light of the sun pervades the air to get through to the ground.
The concept common to both semantic fields is BRIGHTNESS, it seems to me.