Stress is defined as: to place emphasis on; to make emphatic; emphasize. When speaking or pronouncing a word, a particular syllable within a word might be spoken with more or less emphasis. This emphasis (or lack thereof) is referred to as a stressed or unstressed syllable.

Examples of Syllable Stress

The word “rebel” has multiple pronunciations and meanings. When used as a noun versus a verb, the syllables have different emphasis (stress) attached to it depending on you use. Thus the words are pronounced differently. For example:

1) “I am a rebel soldier.” In this instance of the word rebel (A noun defined as: means a person who rises in opposition) the SECOND syllable is stressed.
re-BEL   re (unstressed) BEL (stressed)
/ˈre-bəl/ - accents in pronunciation keys indicate the stressed syllable
2) “I will rebel against the wishes of my parents.” In this instance of rebel (A verb defined as: to rise in opposition) the FIRST syllable is stressed.
RE-bel   RE (stressed) bel (unstressed)
/re-ˈbəl/ - accents in pronunciation keys indicate the stressed syllable
That difference in the weight, emphasis, or accent of the syllable is referred to as stress.

Another example we’ll use is the word “diarrhea” (That's a fun word to say).

Pronounce diarrhea. Can you determine how many syllables (changes in stress) are in diarrhea and which syllables are stressed and unstressed?
Diarrhea has 4 syllables: di-ar-rhe-a
Diarrhea is pronounced DYE-uh-REE-a
/ˈdī-ə-ˈrē-ə/ - accents in pronunciation keys indicate the stressed syllable
As you can see and hear, the first and third syllables are stressed. The second and fourth syllables are unstressed.

Syllable Stress and Poetry

In poetry stress is integral and associaed with the terms "foot" and "meter". A group of syllables, often having a primary accent on one of the syllables and forming a major unit of poetic rhymth is referred to as a foot. While meter is the verbal rhythm making up a foot.

More poetry related information on meter and foot...

...more to come...