Cutting a currently growing shoot back to a bud is known as what type of pruning?

Cutting a currently growing shoot back to a bud is specifically referred to as heading back. This technique is commonly employed in horticulture to encourage new growth and to promote a bushier, denser plant form. By cutting above a bud, the plant is stimulated to produce new shoots from that bud, leading to a more balanced and manageable growth habit.

Heading back is particularly useful for maintaining the size of shrubs or training young trees, allowing for better sunlight penetration and air circulation within the plant. This method contrasts with thinning, which involves removing entire branches to reduce the density of the plant without necessarily altering the overall size, and shaping, which focuses on forming plants into a desired aesthetic shape rather than stimulating specific growth. Pruning generally refers to any cutting of plants for various purposes, but it does not specify the technique being used. Thus, heading back is the most precise term for the action described in the question.