Accent in poetry refers to the stressed portion of a word. For example:

"Let Us make man in Our image,

according to Our likeness;

let them have dominion over the fish of the sea,

over the birds of the air, and over the cattle,

over all the earth and over every creeping thing

that creeps on the earth"

Genesis 26-27

Now depending on where you place the stress in this poem you will get a different meaning. For example, place the stress or accent on 'Our' and suddenly we have more than one God. Place it on 'them' then, there would appear to be a lot of men already there ready to receive planetary rights. Place it strategically on 'fish', 'birds', 'cattle' then you've got a really nice wrap up with accenting the last 'earth' for emphasis. Of course, where to accent in poetry can be of hot debate.

See also: lexical stress