Q. I am editing a piece that makes several references to unspoken orders. For example: He climbed up the plank and handed the engineer a “go” order. Or, After ten minutes he signaled “stop.” Should these orders be in quotations?

A. Yes. Quotation marks needn’t imply that something was spoken. Your sentences are much easier to read with quotation marks signaling the special uses of “go” and “stop.”