A skilled worker is a worker who has skills.
There is an immigration class called skilled worker where you can apply for permanent residency directly. With permanent residency, you have almost all the same rights as a Canadian citizen.
If you do not qualify to apply for permanent residency directly but you have found an employer, you can apply for a work permit. The work permit can be given either to a skilled person or unskilled. The work permit is tied to the employer. If you have a work permit as a skilled person, you can renew it when it expires. If you are unskilled, you can only get a work permit for 2 years, then have to go home again for 4 months before you can apply again.