From the Arabic root ف-هـ-م (f-h-m), meaning comprehension and understanding. The root appears across Classical Arabic in words like فَهْم (fahm, understanding) and فَهِيم (fahīm, one who understands well). Cognate roots relating to perception and grasp are found across Semitic languages.

In Egyptian Arabic — the most widely understood dialect thanks to media — you'll often hear "فاهم؟" (fāhim?) as a quick check meaning "You get it?" or "Clear?" It's one of the most common classroom and conversational words across the Arab world. Note: the colloquial form فَهَّمَ (fahhama) means "to explain to someone" or "to make someone understand," a useful and common causative form.