If two things are akin, then they're similar or related. A cupcake is akin to a cake and relatives are akin to each other.
If you know the word kin — a relative — then you have a clue to the meaning of akin. People who are related are akin, but the word goes beyond blood relations. Football is akin to the sport of rugby; baseball is akin to the British sport cricket. Mice are akin to rats, and rats are akin to gerbils, hamsters, and squirrels. Things that are akin are alike.