1 : a very thin slice (of tissue or mineral or other substance) for examination under a microscope
2 : an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system
3 : any part of a plant or fungus
4 : the allotment of some amount by dividing something
5 : a small part or item forming a piece of a whole
6 : an abstract part of something