互 is almost always used in compounds: 互相 (mutually/each other), 互联网 (internet), 互动 (interaction), 互利 (mutually beneficial). It is not used alone in modern speech.
The top and bottom horizontal strokes form the 二 frame and serve as the indexing radical. Originally 互 pictured a rope-winder with hooks; the top and bottom bars survive as the 二 pattern that anchors the graph for lookup.
pictograph
互hù
mutual; interlocking hooks
The interlocking middle strokes depict the central hooks of a rope-winding tool, two arms reaching from opposite sides to grip each other. This crossed grip is the source of the 'mutual, reciprocal' meaning that 互 contributes to compounds like 互相 and 互助.
