1. An individual, a group, a structure, or other entity regarded as an elementary structural or functional constituent of a whole. 2. A group regarded as a distinct entity within a larger group. 3. A mechanical part or module. 4. An entire apparatus or the equipment that performs a specific function. 5. A precisely specified quantity in terms of which the magnitudes of other quantities of the same kind can be stated. 6. The quantity of a vaccine, serum, drug, or other agent necessary to produce a specific effect. 7. A fixed amount of scholastic study used as a basis for calculating academic credits, usually measured in hours of classroom instruction or laboratory work. 8. a unit on Native Americans. 9. The number immediately to the left of the decimal point in the Arabic numeral system. 10. The lowest positive whole number.
