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prettygoodwordinvar (in-VAHR) - n., an alloy of iron with 35.5% nickel.
This has a very low coefficient of expansion, making it very useful for precision parts that need to not change size with the temperature, such as watch springs. This is a current trademark and so technically should be spelled Invar, but some dictionaries acknowledge it is often spelled as a generic. If you want to use a generic name instead, that would be FeNi36 (outside USA) or 64FeNi (in the USA). Coined as a shortening of invariable.
---L.
This has a very low coefficient of expansion, making it very useful for precision parts that need to not change size with the temperature, such as watch springs. This is a current trademark and so technically should be spelled Invar, but some dictionaries acknowledge it is often spelled as a generic. If you want to use a generic name instead, that would be FeNi36 (outside USA) or 64FeNi (in the USA). Coined as a shortening of invariable.
---L.
