Two events A and B are independent events if the occurrence of event A is in no way related to the occurrence or non-occurrence of event B. Likewise for independent events, the occurrence of event B is in no way related to the occurrence of event A.
Two events A and B are dependent events if the occurrence of one event say A is related to the occurrence of another event, say B.
The joint probability of two outcomes that are independent is equal to the probability of the first outcome multiplied by the probability of the second outcome (the second outcome may be occurring simultaneously or some time in future), i.e. joint probability of two independent events is equal to the product of their marginal probabilities.
P(A and B) = P(A) . P(B)