"Split down" can be used to describe something that is divided or separated into two parts. However, there are several synonyms for this phrase, which can be used to express the same meaning. One such synonym is "halved," which implies dividing something into two equal parts. Another synonym is "separated," which means to move apart or break up into different parts. Additionally, "parted" can be used to describe something that has been divided or separated into different portions. Finally, "bifurcated" can be used to describe something that has been split or branched into two different directions. Overall, there are many synonyms for "split down" that can be used to express the same meaning.