"The Tangle is the data structure at the heart of IOTA, first introduced in the Tangle whitepaper. IOTA uses a DAG instead of a blockchain to store its ledger,
Thus the "ish" part. I may be mixing iota with hashgraph, but my vague memory of it all is that ostensibly you supposedly get the similar functionality in iota as with a blockchain.
Yes, I could read up on it, but someone might also try to give a general explanation of why the tangle does not suffice to give blockchain-like functionality.