solidus

¹ American  

[sol-i-duhs] / ˈsɒl ɪ dəs /

noun

plural

solidi

1. a gold coin of ancient Rome, introduced by Constantine and continued in the Byzantine Empire; bezant.

2. (in medieval Europe) a money of account equal to 12 denarii.

3. virgule.

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solidus ² American  

[sol-i-duhs] / ˈsɒl ɪ dəs /

noun

Physical Chemistry.

1. (on a graph of temperature versus composition) the curve connecting the temperatures at which a solid solution is in equilibrium with its vapor and with the liquid solution, and therefore connecting melting temperatures of solid solutions.

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solidus British  

/ ˈsɒlɪdəs /

noun

1. a technical name for slash

2. a gold coin of the Byzantine empire

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solidus Scientific  

/ sŏl′ĭ-dəs /

plural

solidi

1. The maximum temperature at which all components of a mixture (such as an alloy) can be in a solid state. Above the solidus some or all of the mixture will be in a liquid state.

2. See illustration at eutectic Compare liquidus

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Etymology

Origin of solidus¹

1350–1400; Middle English < Late Latin solidus ( nummus ) a solid (coin), a gold (coin)

Origin of solidus²

1900–05; < Latin: solid

Explanation

When someone uses the word solidus, they're either talking about an ancient gold coin and/or the punctuation mark also known as a slash. Solidus comes from the Late Latin nummus solidus, "solid coin," a reference to thick Byzantine Empire coins made of pure gold. The word shilling evolved from solidus, and later the slash between shillings and pence in English prices (eventually replaced by a decimal point) also came to be called a solidus. You use a solidus whenever you write a date this way: 6/19/1805, or a choice between two options like this: vanilla/chocolate.

Example Sentences

Here is a little graphical palate cleanser: we visualized the life cycle of the parasite Schistocephalus solidus, which requires ingestion by a copepod, a fish and a bird—in that order—to survive and reproduce.

From Scientific American • Dec. 14, 2022

The parasitic cestode Schistocephalus solidus requires a much larger host—specifically, a three-spined stickleback fish—to grow in and then a bird to breed in.

From Scientific American • Sep. 29, 2022

Partial melting occurs when the geothermal gradient line crosses the solidus line.

From Textbooks • Jan. 1, 2017

Decompression melting, plus an addition of heat, shifts the geotherm across the solidus.

From Textbooks • Jan. 1, 2017

Fr. sou, formerly sol, a halfpenny, comes, like Ital. soldo, from Lat. solidus, the meaning of which appears also in the Italian participle soldato, a soldier, lit. a paid man.

From The Romance of Words (4th ed.) by Weekley, Ernest