Plain-English definition
A wrapper is one thing representing another: wrapped BTC on another chain, a tokenized fund share, a bridge receipt, or a token that references an off-chain asset.
Wrappers are useful because they make assets portable. They add risk because you now depend on the wrapper issuer, bridge, custodian, or legal structure as well as the asset itself.
Why it matters
Wrapper matters because crypto markets can look precise while still being shallow, crowded, or poorly sourced. A useful read is not just the number. It is the number, the size behind it, the context around it, and the part it cannot explain.
Simple example
A simple Wrapper example is a reader comparing two venues with the same headline price but different depth. The deeper venue can absorb more capital before the trade, peg, or yield reading starts to move against the user.
How Bathymark uses this term
Bathymark uses Wrapper to translate open market data into live liquidity readings. When the term touches a live page, the reading links back to the relevant chain, protocol, stablecoin, DEX, perps, or Signal so the source remains checkable.
Common mistake
The common mistake is treating Wrapper as a complete signal by itself. Bathymark treats it as one instrument: useful when read beside liquidity, source, size, and what the number cannot prove.