# Sierra

/siˈɛɹə/ (US) · /siːˈeəɹɐ/ (UK)

Source: https://englishreference.com/word/sierra
Updated: 2026-08-15

## Senses

### 1. mountain range

noun · CEFR C1 · Literary

a long line of mountains with sharp, uneven tops that look like the teeth of a saw.

For teachers: a range of mountains with a jagged or serrated ridge, especially in Spain or Spanish-speaking America.

- The sun set behind the high sierra, casting long shadows over the valley.
- The expedition struggled to navigate the rugged terrain of the high sierra, where the jagged peaks made traditional mapping nearly impossible.

Usage: Often used as a proper noun in geographical names like 'Sierra Nevada'.

### 2. phonetic alphabet

noun · CEFR C1 · Technical

the word used for the letter 'S' when speaking over the radio to avoid mistakes.

For teachers: the standard code word for the letter 'S' in the NATO/ICAO phonetic alphabet.

- The pilot confirmed the tail number as Alpha-Bravo-Sierra.
- To ensure clarity over the static-filled radio channel, the operator spelled out the coordinates using Sierra and Tango.

Teaching tip: Learners in aviation, maritime, or military contexts will encounter this as a standard communication tool.

## Examples

- The sun set behind the high sierra.
- The hikers spent three weeks crossing the rugged sierra, navigating steep passes and rocky ridges.
- Geologists study the sierra to understand how tectonic forces pushed these jagged granite peaks upward over millions of years, creating a natural barrier that dictates the local climate.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.