radical sign
Low (Specialist Technical)Formal, Academic, Technical
Definition
Meaning
The symbol (√) placed before a number or quantity to indicate the extraction of a root, most commonly the square root.
Can refer more broadly to the symbol itself, used in mathematical notation and logic. In historical printing contexts, it might refer to a marking indicating a change or deletion.
Linguistics
Semantic Notes
The term is almost exclusively mathematical. 'Radical' alone can refer to the entire expression under the root sign. The 'sign' is the graphical symbol.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or use. Terminology is identical in mathematical contexts.
Connotations
Purely technical and neutral.
Frequency
Equally low frequency in both dialects, confined to mathematics education and texts.
Vocabulary
Collocations
Grammar
Valency Patterns
[The/This] radical sign √ indicates...Apply the radical sign to the radicand.The expression under the radical sign is called the radicand.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “No common idioms.”
Usage
Context Usage
Business
Not used.
Academic
Central to mathematics, physics, and engineering notation.
Everyday
Rare, only in specific educational contexts (e.g., helping with maths homework).
Technical
Precise term in mathematical typesetting, computer algebra systems, and engineering calculations.
Examples
By Part of Speech
noun
British English
- You must write the radical sign clearly before the radicand.
- The history of the radical sign dates back to the 16th century.
American English
- Don't forget to draw the radical sign over the entire expression.
- In the equation, locate the radical sign first.
Examples
By CEFR Level
- In maths, we use a radical sign to show a square root.
- The number under the radical sign is 16.
- To solve, you must first isolate the term containing the radical sign.
- The expression under the radical sign must be non-negative for real roots.
- The denesting of radicals requires manipulating expressions under the radical sign.
- Rendering the radical sign correctly in digital typography requires specific font support.
Learning
Memory Aids
Mnemonic
Think of a plant's RADICAL (root). The sign looks like a checkmark √ 'checking' what the root is.
Conceptual Metaphor
NOT APPLICABLE (Highly technical symbol).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Не переводите как "радикальный знак" в бытовом смысле. Это "знак корня" (математический).
- Слово "radical" здесь не имеет значения "крайний" или "революционный".
Common Mistakes
- Pronouncing 'radical' as in 'radical politics' instead of /ˈrædɪkəl/.
- Confusing the radical sign (√) with the check mark (✓) or the tick mark.
- Using 'radical sign' to refer to the root itself (e.g., √9) rather than just the symbol (√).
Practice
Quiz
What is the primary function of the radical sign (√)?
FAQ
Frequently Asked Questions
The square root sign is the most common type of radical sign (where the root index is 2). The radical sign can represent any root (cube root ∛, fourth root ∜, etc.) when an index is specified.
No, it is exclusively a noun. The action is 'to take a root' or 'to apply the radical sign'.
It is called the radicand.
It is derived from the letter 'r' (for 'radix', the Latin word for 'root'), in 16th-century manuscript form.