Stress is an extra force in speaking,or prononciation of a word or a syllable.
We find stress in two levels.
Word stress,is a stress in the level of a word.That is which syllable of the word is stressed.
Sentence stress, we find the stress at the level of a sentence.That is which words are stressed.For exemple,content words like verbs nouns adverbs,and adjectives. The other words will be unstress ,like pronouns,articls propositions,auwilaury verbsand intosifitors.