A person who economizes; someone who spends carefully and avoids waste. Also, a mechanical device that improves efficiency or reduces waste.
From 'economize' plus the agent suffix '-er.' American English spelling; British uses 'economiser.' Can denote either a person or a machine.
Modern car engines have economizers—mechanical or electronic devices that optimize fuel use—and ironically, car designers face pressure to economize on these same devices to keep vehicle prices down.
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