Conserve

Engineering definition

Consistent with a law of conservation, which says that a particular measurable property of an isolated physical system does not change as the system evolves over time. These laws pertain to the conservation of energy, linear momentum, angular momentum, and electric charge. This meaning is more system specific than the layman understanding of using carefully or sparingly, and applies to fundamental engineering research, particularly thermodynamics.

Medical definition

To keep (a quantity) constant through physical or chemical reactions or evolutionary changes. This concept may be applied when examining reactions or cell developments, and is used in immunology and pathology.

Confusion

Engineers and doctors understand that to conserve means to avoid waste.