means A thin, sharp sliver of wood (or similar material) broken off from a larger piece, especially one that lodges painfully in your skin.

from From Middle Dutch and Middle Low German 'splinter,' a sliver or chip, related to 'split' and the broader Germanic family of words for things that crack and break apart. The sound itself almost does the work — that crisp 'spl-' cluster echoing across 'splice,' 'splice,' and 'split,' all hinged on the idea of one thing parting violently into thinner ones.