a little
纔 centers on a small amount or degree: a little, barely, or just a trace. It expresses minimal quantity or extent.
纔 combines 糸 (thread) with 毚, which likely contributes the sound. The thread component may relate to the idea of something fine or slight, but the exact historical development is uncertain.
The left side 糸 suggests a fine thread, and the complex right side 毚 looks like a tiny, intricate tangle. Together they picture something so small it is barely there—just a little.
For サン, imagine a tiny sunbeam (サン) shining through a needle's eye, so small it is just a little light: sun -> サン, and the thread 糸 is barely visible.
just a tiny bit