Presets are usually used in reference to Lightroom. The comparative term for Photoshop would be Actions. Presets are a pre-set position of all or some of the Lightroom Develop module sliders that impart a very specific look and feel to an image. There are millions of presets both free and paid-for that you could download from the internet and accentuate your work.
Some of these are designed to add simple effects like pulling down the exposure. There are others which are more radical and therefore give a very particular effect like making things golden warm.
Leading photographers prefer to create their own presets which help them quicken up the whole post-processing chore as well as give their photos their unique touch. You can make presets very easily. All you have to do is go to the Develop Preset panel. Click on Create a new Preset, enter a name for the Preset and save it.