bulb 
/ˈbʌlb/ noun
plural bulbs /ˈbʌlb/ noun [count] 1 : light bulb
▪ a 100-watt bulb ▪ fluorescent bulbs — see also dim bulb 2 : a rounded part of some plants that is under the ground and that grows into a new plant during the growing season
▪ tulip bulbs — see color picture 3 : a part that has a rounded shape
▪ the bulb of the thermometer/eyedropper
▪ a 100-watt bulb ▪ fluorescent bulbs — see also dim bulb
▪ tulip bulbs — see color picture
▪ the bulb of the thermometer/eyedropper
