mysql - Meaning of "n:m" and "1:n" in database design

Question

In database design what do n:m and 1:n mean?

Does it have anything to do with keys or relationships?

Answer 1

m:n is used to denote a many-to-many relationship (m objects on the other side related to n on the other) while 1:n refers to a one-to-many relationship (1 object on the other side related to n on the other).