From the Latin verb haereo and its past tense form haesi, meaning “to stick (to), cling (to),” we get the English word adhesive, which makes one thing “stick to” another. We also get the words adhere (“to stick to”) and adherent—someone who “sticks to” their beliefs. If we change the prefix from ad- (“to”) to co- (“together”), we can describe a group of friends that “sticks together” as cohesive, a person whose words “stick together” intelligibly as coherent, and the opposite as in(“not”)coherent.