enarch means to arch. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From en- + arch.
verb
- To arch.“1420-1422, John Lydgate, Siege of Thebes
And in a porche bilt of square stonys,
Ful myghtely enarched envyroun,
Wher the domys and plees of the toun
Weren execut and lawes of the kyng”