Which characteristic of an individual letter remains constant?

The name of an individual letter remains constant regardless of the context in which it is used. Each letter of the alphabet has a specific name that does not change. For example, the letter "B" is always referred to as "B," whether it appears in a word, as part of a sentence, or in isolation.

While the sound of a letter can vary depending on factors such as its position within a word and local accents, the name remains the same. Similarly, the form (or appearance) of the letter can change as different fonts or styles are used, but the underlying letter remains identified by its name. Therefore, the consistency of a letter's name is a fundamental characteristic that is true for all letters in the alphabet.