Relational frames are particular types of relational responding. Relational responding means responding to one stimulus based on its relation to another stimulus or stimuli.
For example, when Jackie plays basketball at the park, she always picks whichever player is tallest to be on her team first. This is a relational response. Jackie is not choosing just any tall player, or the same person each time. She is choosing the tallest player available. Jackie is choosing a player based on their relation (in terms of height) to the other players.