矶 is rare as a standalone word. Most learners encounter it in 洛杉矶 (Luòshānjī, Los Angeles) where it serves as a phonetic transliteration for '-les'. The stone radical 石 hints at its original meaning of rocky shore.
石 (the stone radical) gives the literal substance - 矶 is a rocky outcrop jutting into water, the kind of jetty or rocky islet anglers fish from. Same radical in 砖 (brick), 砂 (sand), 碑 (stele), all stone-themed.
几 jī provides the sound. The simplified form 矶 (from traditional 磯) replaced the older phonetic 幾 with the much simpler 几, which shares the jī reading. Same phonetic shortcut applies to 机, 饥, 讥 across the simplification reform.
