What are summer associates and partners in law?

I am confused by these 2 jobs can anyone explain?

Summer associates are people hired only for the summer to help out–usually law students so they can get first hand experience by working in a law firm. However, the work expected from summer associates usually isn’t so important that if they can’t or don’t finish it the case won’t be affected (but the summer associate’s review may be affected). They make arrangements with a law firm, or with several different law firms, to work a certain number of weeks in the summer, get paid a pretty good salary for those weeks, are wined and dined as they won’t be when they become full-fledged attorneys and are supposed to be supervised and mentored by the experienced attorneys in the firm.

The partners in a law firm are the big executives and basically “own” the firm. They make the most money and charge the most hourly rate from the clients. They have the most experience and often carry the most well-known and respected reputation. They make many of the decisions as to which direction the firm will go, like the board of directors of a corporation. To become a partner, usually a regular associate (full-time attorney) has to work a certain number of years doing a lot of the more monotonous work, researching and writing a lot of the documents, reviewing files and documents, coordinating the team working on a case, seeing to a lot of the picky things since they don’t charge as much from the client. If the associate has been doing a good job for the number of years expected, possibly even bringing in business, he or she may be offered a partnership (to join the other partners) which usually entails paying a certain amount of money into the firm but it also ups their own pay rate.

Deferred Associates: Juvie Judge – Job #2