“Interdigitate” is a 19th-century merger of Latin pieces. The prefix “inter-” (meaning “between”) joins “digitus” (meaning “finger or toe”) to evoke the image of fingers meshed together in sequence. Most people have a personal preference toward how they interdigitate (in the literal sense of interlocking their fingers). Some people prefer to have their right thumb on top when they clasp their hands, others prefer to have their left on top, and a third group of ambidextrous people are comfortable either way. Beyond having ruled out a genetic explanation for this preference, researchers do not know why the preference exists. The word “interdigitate,” however, can be used for any interlocking pattern, not just fingers.