separatrix

American  

[sep-uh-rey-triks, sep-uh-rey-] / ˈsɛp əˌreɪ trɪks, ˌsɛp əˈreɪ- /

noun

plural

separatrices, separatrixes

1. something that divides or separates, as the line between light and dark areas on a partially illuminated surface.

2. virgule.

3. Mathematics. one of several symbols for separating components of a number, as a decimal point or comma.

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separatrix British  

/ ˈsɛpəˌreɪtrɪks /

noun

1. another name for solidus

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Etymology

Origin of separatrix

1650–60; < New Latin sēparātrīx, Late Latin; separator, -trix

Explanation

A separatrix is a punctuation mark that separates alternative words, like "either/or" and "he/she/they." You probably call a separatrix a slash, but other terms for this mark are solidus and virgule. It's used for fractions in math, and to indicate dates like 10/14/2025. A separatrix is also shorthand for the word or: "Do you like me? Yes/No." In proofreading, this mark indicates a replacement word or sentence for text that's been crossed out. Separatrix has a Latin root that means "to pull apart or separate."