n reflecting on important articles published in The Plant Cell, we consider a letter from Eran Pichersky in 2005, which posed the question “Is the concept of regulation overused in molecular and cellular biology?” (Pichersky, 2005). Pichersky noted that authors often use the term loosely and erroneously. For example, if a gene regulates the production of the protein it encodes, then all genes are regulatory and the term becomes meaningless. Similarly, showing that a product is no longer made when an enzyme is knocked out does not mean that the enzyme is regulatory, but rather simply that it is necessary. The misuse of the term “regulatory” persists, and there remains a need to define and use this term more precisely.