Definition: "A cluster of lobe-like projections of glomeruli within the glomerular layer of the ofactory bulb, each cluster being referred to by their directionality (e.g. medial vs. lateral, and/or relative size, e.g. small v intermediate). Olfactory receptor neuron axons (ORNs, yellow) incoming from the olfactory nerve (ON) form distinct medial (MC), intermediate (IC), and lateral (LC) clusters in the glomerular layer."