The term fruiting spurs does not have a universally agreed upon definition. Most fruit scientists consider fruiting spurs to be short shoots, usually less than 6 inches long, with a rosette of leaves just behind a fairly large bud at the tip of the shoot. the large bud (the terminal bud) is usually a flower bud, from which a cluster of five flowers will emerge the following spring. Spurs arise from portions of a branch that are at least two years old. The density or the number of spurs per foot of branch length is characteristic of a cultivar or strains of cultivars. For example, spur-type strains of 'Delicious', 'Golden Delicious' and 'McIntosh' have higher densities of fruiting spurs than non-spur strains. Cultivars such as 'Tydeman's Red' and 'Rome Beauty' have low densities of spurs.
-Rich Marini, Penn State University