The distance between nodes (bud sites) along the main stem. Tight internodal spacing typically correlates with larger, denser buds stacked closely together; wider spacing can result in buds that are further apart.
Dakota discusses internodal spacing at day 11 flower as an early indicator of final bud size. He notes the Kerosene Krash spacing was looking 'good, tight' and anticipated it would produce big buds. By week 4 he describes bud-on-bud-on-bud stacking.
Discussed in: Ep 002