Which can help readers define words?

1. pronounciation
2. etymological patterns
3. parts of speech
4. stressed syllables

All of the above options can help readers define words. Each one provides a different aspect of understanding and defining a word:

1. Pronunciation: Knowing how to pronounce a word correctly can provide clues to its meaning and origin.

2. Etymological patterns: Understanding the roots and origins of words through etymology can help readers decipher the meanings of unfamiliar words.

3. Parts of speech: Identifying the part of speech of a word (e.g., noun, verb, adjective) can give readers insights into how it functions in a sentence and what it means.

4. Stressed syllables: Recognizing where the stressed syllables are in a word can assist readers in properly pronouncing and understanding its meaning.