branching stream
汊 centers on a watercourse that splits: a branching stream or river fork. The single given meaning is a specific geographical feature, not a broad abstract concept.
汊 combines 氵 (water) with 叉, which likely contributes both sound and the idea of forking or branching, reflecting a branching stream.
Water 氵 meets a fork 叉: picture a stream splitting into two branches at a Y-shaped junction.
For サ, imagine a small branching stream in a serene garden, with a sign that says 'Sa' (like the first syllable of 'sapphire') to mark the spot: Sa -> サ.
—