Long Tail Keywords
Long Tail Keywords - are search phrases that are highly relevant to your specific niche, product, service or topic, have low competition level, comparatively low search volume and, generally, consist of 3+ words. The longer and more specific keyword phrases are, the more visitors are likely to use it when they are searching something they need specifically.
For example: let's consider a generic keyword – «candy». The keyword has extremely high competition (over 15 000 apps on the Play Market were found) and it means that a user wasn't going to find something special. If he wanted to find a special app he would type "candy soda mania puzzle" and find an app he was searching, as this keyword is long-tail, less competitive and more targeted (only 1 800 apps were found by chosen keyword).