isotach
Very Low / TechnicalScientific / Technical
Definition
Meaning
A line on a map or chart connecting points of equal wind speed.
In meteorology and oceanography, a contour line or surface along which the speed of flow (wind or current) is constant.
Linguistics
Semantic Notes
Primarily a technical term from meteorology, physical geography, and fluid dynamics. It belongs to the class of 'iso-' terms (isobar, isotherm). It describes a measured, objective condition, not a subjective observation.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or semantic differences. Spelling conventions are identical.
Connotations
Neutral, purely technical in both varieties.
Frequency
Extremely rare in general usage in both varieties, used exclusively within specific scientific fields.
Vocabulary
Collocations
Grammar
Valency Patterns
The map shows [an isotach] of [50 knots].The meteorologist plotted the [isotachs] for the jet stream.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Used in meteorology, geography, and environmental science publications and lectures.
Everyday
Virtually never used.
Technical
The primary context. Found in weather analysis, atmospheric research papers, and specialized charts.
Examples
By Part of Speech
adjective
British English
- The isotach analysis revealed a core of high-speed winds.
American English
- The isotach chart was crucial for the flight planning.
Examples
By CEFR Level
- Weather maps can have lines, called isotachs, that show where the wind is equally strong.
- The forecast model output included a plot of 300-mb isotachs, clearly delineating the position of the subtropical jet stream.
Learning
Memory Aids
Mnemonic
Think: 'ISO' means 'equal' (like in isobar for equal pressure) and 'TACH' relates to speed (like tachometer). So, isotach = equal speed.
Conceptual Metaphor
A contour map of the wind's 'landscape', where valleys and ridges represent areas of slower or faster air movement.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation. 'Изотаха' is the correct transliteration, but the concept is best explained as 'линия равной скорости ветра'. Do not confuse with 'изотерма' (isotherm) or 'изобара' (isobar).
Common Mistakes
- Mispronouncing as 'iso-tack' (like thumbtack) instead of 'iso-tak' (like tachometer).
- Confusing with 'isotherm' or 'isobar'.
- Using it in a non-scientific context.
Practice
Quiz
What does an isotach represent on a weather map?
FAQ
Frequently Asked Questions
No, it is a highly specialized technical term used almost exclusively in meteorology and related sciences.
An isotach connects points of equal wind speed, while an isobar connects points of equal atmospheric pressure.
No, 'isotach' is solely a noun. The related action would be 'to plot isotachs' or 'to analyse isotachs'.
In academic papers, technical weather forecasting discussions, and on specialized meteorological charts, particularly for aviation or upper-atmosphere analysis.