Microbe/ˈmaɪkrəʊb/ Definition 1 of 2Pro Tip 1/3Disease Association Often used when talking about illnesses caused by invisible organisms. Washing hands removes harmful microbes to prevent sickness. Pro Tip 2/3Scientific Context Commonly found in health and science discussions, less so in everyday conversation. The lab focuses on microbe research to develop new vaccines. Pro Tip 3/3Neutral Connotation The term itself is neither negative nor positive; context shows if the microbe is harmful or helpful. Certain microbes can improve our immune system.