The fifth letter of many Semitic alphabets (Phoenician, Aramaic, Hebrew, Syriac, Arabic and others).
"The heh is the fifth letter shared by several Semitic scripts such as Phoenician and Hebrew."
In plain English: Heh is an informal way of saying laugh, often used to show amusement at something funny or silly.
"The comedian's stand-up routine was mostly just hehs and grunts until the final joke made the whole audience laugh out loud."
Weak amusement, sometimes signaling boredom.
"Heh... I guess that's all there is to say about the meeting today."
Onomatopoeia of a weak laugh.