verb/bu.kle/
to buckle (to fasten); to curl (make curly); to tie up, to finish up (e.g. an affair or case); to shut; to curl up (become curly)
“Je fermerai fenêtres et persiennes / Je bouclerai la porte à double tour / Et en faisant une flambée, Hélène / Je te réchaufferai, je te réchaufferai” — I will close windows and shutters / I will shut the door with two turns of the key / And by making a fire, Helen / I will warm you up, I will warm you up
14th century, from boucle