In British dialect, “fettle” means “to set in order” or “to get ready,” coming from the Middle English “fetlen,” meaning “to shape, prepare.” The noun “fettle” is related, referring to a healthy state of being. You might be familiar with the phrase “in fine fettle,” a folksy way to say something is in good condition. The verb “fettle” is also used in specific fields such as glassblowing and metallurgy to refer to lining the bottom of a hearth with sand or gravel. When a furnace is fettled, it’s put into fine fettle.