Anything that refers to a previous generation of a subject/idea/object/etc. Typically, they are highly regarded and sometimes the very thing that started it all.

from back in the day

A positive appellation referring to when things weren't flashy but empty of substance, were done by hard work, didn't pander to the lowest common denominator, and required real skill. Labour-saving devices, shortcuts that reduce quality and quitting before the task is done are not characteristics of "old school."

In reference to computer games, refers to a game that had substantial playability without flashy graphics or eye candy. Old school gamers appreciate difficult maneuvers, careful planning, and scorched earth policies.

In reference to role-playing games, old school refers to games that tested players' wits, could kill off careless characters, and required dedication and inner strength to play. Old school games didn't pander to the ideas that everyone is created equal, that all options are open to all races, that the markets were somehow free, and that a quasi-medieval society could have near 100% literacy.

See also classic.

1) Retro
2) As Before (as something was done, said, etc.)

The way things used to be done.

1. Music from back in the day, the last decate and before.
2. A. Some thing that past is time or it's fashion, or
B. a bring back memory of of a thing in the respectable way.

1. Old School (sp. Ol Skool) is a term that originated sometime in the very early 1990's with the introduction of Hip-Hop (which was the dance anyone could do, originaly consisting of foot-work and had its roots in jazz-funk). Old School refers back to 1984 when break-dancing was at its prime,because so many moves had to be studied and practiced just as one would learn in school.

To "take some-one to school", meant to either teach and instruct them or show by greater example how a move should be properly executed.

Given the new popularity of Hip-Hop in the early 1990's, many of the younger generations only learned how to perform the Hip-Hop moves (those who only knew Hip-Hop were refered to as the New-School).

Note: Anything that took place within the 1990's is refered to as, "back in the day".

2. Old School, Originaly the term was first used to differentiate between Break-Dancing and Hip-Hop.

3. An era that is marked by the very first computer generation; those who had the first personal computers (which soley ran off basic language and consisted of no hard drive) like the CoCo, Commodore, Apple, Pong, etc. This era occured after the baby-boomers of 1945-1965.

Masturbating to a magazine. Hardcore old school involves the lingerie section of an old Sears catalog.

The way things used to be done that is more difficult than the way they are usually done now, but also more effective.