I just got asked a question about quantum entanglement. Can someone please give me a basic understandable of what it is​

If you want the definition I will tell you the definition of what it means.

a property of a set of subatomic particles whereby a quantum characteristic (such as spin or momentum) of one particle is directly and immediately correlated with the equivalent characteristic of the others regardless of separation in space
In quantum entanglement, subatomic particles maintain a relationship—for instance, vibrating when the other vibrates—even when separated and even if they are at great distances from each other.

Hope it helps you.