What is the phonetic alphabet word for the letter 'S'?

The phonetic alphabet is designed to ensure clear communication, especially in situations where misunderstanding could occur, such as in aviation, emergency services, or military operations. The correct word for the letter 'S' in the phonetic alphabet is "Sierra." This term is universally recognized and represents the letter 'S' in a way that is distinct from other letters and can be easily understood over radio or telephone communications, which can often be noisy or unclear.

"Sierra" was chosen because it sounds sufficiently different from other phonetic alphabet words, thereby reducing the potential for confusion with similarly sounding letters. Each word in the phonetic alphabet is selected with clarity and ease of understanding as a priority. The other options, while they may begin with the letter 'S', do not represent any accepted standard in the phonetic alphabet used in communication protocols.