The term 'quantity of wool' refers to the AMOUNT of wool that is available for use. Wool is a natural fiber that is obtained from sheep and other animals, and is used in the production of clothing, blankets, and other items. It is also used in the production of yarn and other fabrics. The three-letter answer to this crossword puzzle is 'AMT', which stands for 'AMOUNT'. Therefore, the answer to the question 'quantity of wool' is 'AMOUNT of wool'.