A separate ledger connected to bitcoin through a peg and its own security model.
Sidechain is best understood as part of a system rather than as an isolated definition. Its related coordinates show the mechanisms, incentives and historical records that give the term practical meaning.
Sidechain sits between protocol rules, economic incentives and software operated by independent participants. In Bitcoin, no component is authoritative by itself: miners propose history, fully validating nodes enforce validity, and users decide which rules and software they accept.
Understanding Sidechain helps distinguish a verifiable Bitcoin mechanism or historical record from slogans, products and market narratives.
For the clearest picture, read this entry together with Bitcoin, Liquid Network. The reverse links also lead from Liquid Network, Merged mining, Adam Back.
Linked to related atlas coordinates
Grounded in a source record
Explains function and trade-offs
Part of the open Bitcoin knowledge graph