A representative of Reed’s Photo Mart, Inc. (Reed’s) (defendant) prepared a purchase order for labels from Monarch Marking System Company (Monarch) (plaintiff). The purchase order listed the desired quantity of four different types of labels as “2M” and the quantity of a fifth type of label as “4MM.” Monarch printed and shipped 4 million of the fifth type of label to Reed’s. Reed’s refused the shipment, arguing that it had meant to purchase 4,000 labels. Monarch sued Reed’s for the price of the 4 million labels. The jury found that the term “MM” meant 1 million by custom and usage in the trade and refused to find that Monarch knew that the order for “4MM” labels was a mistake. Based on the jury verdict, the trial court awarded Monarch the cost of the 4 million labels. Reed’s appealed, and the court of civil appeals reversed, finding that the trial judge erred in failing to submit the issue to the jury of whether Monarch should have known that Reed’s had made a mistake in the purchase order. Monarch appealed.