Depicts wind rustling through a tree branch (丂). Based on the original meaning "exhale, shout", now written as 呼. The current meaning is a phonetic loan.
interrogative or exclamatory final particle; (classical particle similar to 於|于[yú]) in; at; from; because; than; (classical final particle similar to 嗎|吗[ma], 吧[ba], 呢[ne], expressing question, doubt or astonishment)