Zero

zero
verb, transitive. To concentrate firepower on the exact range of, usually used with “in,” as “zero in”; to adjust an instrument to zero; to phase out or reduce to zero.
verb, intransitive. To adjust fire, as of artillery, on a specific target, usually used with “in; to move near to or focus attention as if on a target.
Also a noun and an adjective.

The kid was busy at the sink, finishing the most recent task Aaron had assigned him. Aaron decided to let him carry on and continued assembling ingredients on the table. The final thing he fetched was a small digital scale--his latest acquisition. He adjusted its unit value to pounds and ounces, then looked up as his assistant approached.

“Next?” the kid asked him.

“We’re going to make an Italian cream cake.” Aaron made a sweeping gesture across the table to indicate the containers and measuring implements he had gathered there. “I’ve done the mise en place,” he continued, hoping that he wouldn’t have to explain what that phrase meant.

“Thank you,” the kid said with a nod.

“Good. I’ll talk you through it.” Aaron stepped back and indicated that the kid should stand before the scale. “First, check the units on the scale. Look at your recipe. What should the scale read?”

“Pounds and ounces.”

“Correct. Place the large bowl on the scale, then zero it by pressing the ‘Tare’ button.” Aaron watched as the kid followed the instruction, then mused, “it seems as if ‘tare’ ought to be a verb. If it was, it would be less to say. I could just tell you to put the bowl on the scale, then to tare the scale. More efficient.” The kid met Aaron’s gaze and nodded. “Start with the flour.”

After the kid had weighed out the correct amount, Aaron instructed him to zero the scale again and add the next ingredient on the list. The process continued through the rest of the ingredients that had to be weighed, then those that had to be measured. The kid whisked the bowl of dry ingredients to remove any lumps, turned to the liquids and combined them, then gradually added the latter to the former. The cake, when it was done, was as good as any that Aaron’s bakery had ever produced.

The next morning, the kid was waiting at the shop door when Aaron arrived. He returned Aaron’s greeting, then said, “’Tare’ is a verb, sir. I had to look in two dictionaries, but in one of them it’s defined as a verb that means 'to zero.' So, I guess you can tell your trainees to ‘tare the scale.’”

Aaron smiled as he disabled the alarm. The kid was thorough, and capable of following up even without being told to. He might do, Aaron thought. Yes, he just might do.

Definitions adapted from The New Oxford American Dictionary, Oxford University Press, Inc., 2005 (eBook Edition, copyright 2008), and from Webster's Seventh New Collegiate Dictionary, G. & C. Merriam Company, Publishers, Springfield, Massachusetts, USA, 1965, depending on which is more convenient to hand.