1a rounded underground storage organ present in some plants, notably those of the lily family, consisting of a short stem surrounded by fleshy scale leaves or leaf bases and lying dormant over winter.Compare with corm, rhizome.
a plant grown from a bulb.
2an object with a rounded or teardrop shape like a bulb, in particular.
a light bulb.
an expanded part of a glass tube such as that forming the reservoir of a thermometer.
a hollow flexible container with an opening through which the air can be expelled by squeezing, such as that used to fill a syringe.
a spheroidal dilated part at the end of an anatomical structure.
late Middle English: via Latin from Greek bolbos 'onion, bulbous root'