To recap is to briefly explain something by giving just the main points or details. You might write a popular blog in which you recap episodes of your favorite TV shows.
Some shows on television begin with a recap of the previous episode, so viewers can refresh their memories about what's happening in the story so far. A book review is sometimes nothing more than a recap of the plot. And if you miss an important meeting of your Spanish club, the secretary's minutes will recap what was discussed. Recap is a shortened form of recapitulate, "summarize," from the Latin recapitulare, "go over the main points again."