Pesasibul kannab ladinakeelset nime Allium cepa Aggregatum-rühm. Harilikust sibulast erineb pesasibul vaid veidi väiksemate sibulate poolest, mis moodustavad suuri pesakondi. Pesasibula söömine hingeõhule sibulalõhna ei jätvat.
Shallots are perennial plants but are often cultivated as annuals. The leaves are short, small, cylindrical, and hollow, and the flowers are typically lavender or red and borne in a compact umbel. The small bulbs develop in clusters on a common base, much like the garlic plant.