The modern-day expectations of a Turing computer capable of solving all computational problems.
Turing Complete is the term used to describe still-futuristic machines or algorithms that can solve all computational problems, regardless of their levels of complexity. Such machines only require time and sufficient processing power. In blockchain, these machines are used to determine the level of network complexity and operation, which also indicates the efficiency of the blockchain for carrying out tasks.
Turing Complete is not necessarily sought-after in blockchain applications since it also has limitations. Thus, Bitcoin, for example, is Turing Incomplete, thereby keeping the blockchain somewhat straightforward. On the other hand, Ethereum uses Turing Complete mostly because it requires higher accuracy and complexity for its smart contracts.