mantissa
C2Highly Technical/Specialized
Definition
Meaning
The fractional part of a logarithm, located after the decimal point.
1. (Mathematics) The decimal part of a logarithm (as opposed to the characteristic, or integer part). 2. (Computing, dated) The significant digits of a floating-point number, sometimes used synonymously with 'significand'.
Linguistics
Semantic Notes
In its primary mathematical sense, a mantissa is always positive and less than 1 (e.g., in log₁₀(350) ≈ 2.5441, the mantissa is .5441). The term is sometimes considered archaic or imprecise in computer science, where 'significand' is preferred.
Dialectal Variation
British vs American Usage
Differences
No significant differences in definition or usage. The term is confined to identical technical contexts in both varieties.
Connotations
Purely technical, neutral, and academic in both regions.
Frequency
Extremely low frequency in general language. Equally rare and specialised in both UK and US English.
Vocabulary
Collocations
Grammar
Valency Patterns
the mantissa of [logarithm/number]calculate/extract the mantissamantissa and characteristicVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Never used.
Academic
Used in advanced mathematics, engineering, and historical computer science contexts.
Everyday
Virtually never encountered.
Technical
The only context of use. Precise meaning depends on field: pure mathematics (logarithms) or computing (floating-point representation).
Examples
By CEFR Level
- In mathematics, a logarithm has an integer part and a decimal mantissa.
- To find the number from its logarithm, you must look up the antilog of the mantissa in specialised tables.
- Early computer architectures stored the mantissa and exponent of a floating-point number separately.
Learning
Memory Aids
Mnemonic
Think: 'Man, I need the decimal part!' – Mantissa is the decimal part I need.
Conceptual Metaphor
THE FRACTION IS A TAIL (the mantissa 'tails' the integer characteristic).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'мантисса' (which is a direct cognate with the same meaning). The trap is assuming it's a common word; it's highly specialised in English just as in Russian.
Common Mistakes
- Using 'mantissa' to mean the entire logarithm or number.
- Pronouncing it /mænˈtiː.sə/ (man-TEE-sa).
- Assuming it is a common term in computing; 'significand' is more precise.
Practice
Quiz
In which field is the term 'mantissa' most precisely and commonly used?
FAQ
Frequently Asked Questions
In modern computing, they are related but not identical. The significand includes the implied integer bit in normalized binary numbers, while mantissa traditionally referred only to the fractional part. 'Significand' is the preferred term.
No, by convention, the mantissa of a common logarithm (base 10) is always presented as a positive decimal between 0 and 1.
Virtually nowhere. It is a highly technical term specific to logarithm tables and the底层 of floating-point number representation in computing.
In British English: /manˈtɪs.ə/ (man-TISS-uh). In American English: /mænˈtɪs.ə/ (man-TISS-uh). The stress is always on the second syllable.