Which can help readers define a word?

Etymological patterns
Stressed syllables
Pronunciations
or, Parts of speech?

All of the options listed can help readers define a word to some extent, but the most direct way to define a word is by looking at its parts of speech. Parts of speech provide information about how a word is used grammatically and can help determine its meaning. Etymological patterns, stressed syllables, and pronunciations can provide additional insights and context, but they may not always directly define a word.