bʰleḱ-

“to flash, lightning flash”

Widely acceptedweatherlight

bleach, bleak, black, blanch, blank

Root of Old English blæc "shining, pale" and blæc "black" (from burnt), yielding English bleach, ble‍‌‍‍‍‍‌‍‌‌‌‍‌‍‍‌‍‍‍‌‌‌‌‌‍‍‌‍‌‍‌‌ak, black, blank.

(H)meyǵʰ-“to urinate, to mist”(s)teh₂n-“to thunder”(s)tenh₂-“to crash, to thunder”bʰeh₂-w-“to shine forth, to appear”bʰerǵ-eyo-“to keep brightening, shining”bʰewk-“to shine, gleam”bʰleg-“to shine, burn, flash”bʰlēg-“to shine, to gleam, to burn”