Is parachain a data structure?

Question

In Polkadot docs, Parachain is defined as:

A parachain is an application-specific data structure that is globally coherent and can be validated by the validators of the Relay Chain.

Why have they used the term data structure instead of chain? links to doc

Answer 1

A blockchain is a datastructure essentially. It's a distributed linked-list that uses a consensus mechanism to append blocks and grow the list. A parachain is a blockchain, hence the term makes perfect sense in this case.