To apply force to (a body or structure) causing strain.
To apply emotional pressure to (a person or animal).
To suffer stress; to worry or be agitated.
To emphasise (a syllable of a word).
“Emphasis” is stressed on the first syllable, but “emphatic” is stressed on the second.
To emphasise (words in speaking).
To emphasise (a point) in an argument or discussion.
I must stress that this information is given in strict confidence.