Some more context here is that Reed Solomon and Shamir's Secret Sharing both take some data and produce N pieces (commonly called shards or horocruxes), any K of which can reconstruct the original data (K <= N).

The difference is that Shamir's makes it so that having up to K-1 pieces reveals _no_ information about the original data. You may be able to infer certain data from less than K shards in Reed Solomon.