Alternate source - an additional recording of a concert taped by another member of the audience. In the concert listings, any show with two or more cassette pictures indicates the number of known tapers for that particular show (examples: New York 12-1-77, Tokyo 2-13-81). Any concert listed with two or more CD pictures indicates that multiple sources have been released on bootleg CDs (examples: Tokyo 5-1-75, Tokyo 3-31-76), not that there has been more than one bootleg CD release of the same source (examples: Seattle 3-13-77, Montreal 12-1-78). As new sources continue to emerge, they are labeled numerically in the order that they come out.

Bootleg - an unofficial recording of an artist sold for profit by a company that specializes in producing unofficial CDs (or LPs, back in the day). Note that not all unofficial recordings are bootlegs. In fact, most of them aren't (see definitions of RoIO, Counterfeit, and Pirate, as well as the Wikipedia article on the subject). Bootlegs of rock music first emerged in the 60s and were only available on LP for purchase at the time, before cassette tapes became popular. The cultural stigma of the word "bootleg" still exists to this day that a) all unreleased recordings are to be referred to as bootlegs, and b) all unreleased recordings are hurting record sales. The efforts of common fans and their high speed internet connections have rendered both of those claims to be at least 99% untrue today.

Counterfeit - an imitation of an official release, packaged to look like one

Lineage - a brief piece of information indicating exactly where a recording has been between the original source and the collector, clarifying reasons for any quality loss if applicable

Lossless - a form of digital compression that does not alter the file when compressing it (i.e. FLAC, SHN, APE, etc.)

Lossy - a form of digital compression that alters the file when compressing it, making what has been lost unrecoverable (i.e. MP3, OGG, WMA, etc.)

Pirate - an unauthorized recording sold for profit that contains previously officially-released material

RoIO [Recording of Independent (or Indeterminate) Origin] - any unreleased recording of an artist that has not been bootlegged (see above definition of 'bootleg'). In other words, any recording that has not been released by the artist or a bootleg label is a RoIO, with the exception of pirates and counterfeits of official releases. This includes material taped from the audience, the radio, or soundboard recordings (each are distinguished in the concert listings).

The term "VoIO" also applies for videos. On this website, note that audio taken from videos will not be referred to as RoIOs, so they won't be mistaken as being from another source (see above definition of "alternate source").

Silver - a factory-pressed bootleg on CD (not CDR). Note that some companies produce only CDR bootlegs (such as Breakdown, Trial, and Masterport), probably to save on production costs. In today's world of online file sharing, many bootleg labels now sell material that has been shared online for free by fans and tapers.

Soundboard recording - a recording from the mixing board (note that video feeds are often not the board mix)

Tape generation - the quality lost when a cassette is copied to another cassette. For example, if one copy of a master cassette is made to another cassette, it's referred to as a first generation tape. If this is ripped to WAV, burned to CDR, and copied to another CDR, its lineage can be written in any of the following three ways (with "AUD" indicating it's an audience recording):

AUD > Master Cassette > Cassette > WAV > CDR > CDR
AUD > Master Cassette > 1st Gen Cassette > WAV > CDR (1)
AUD > Master Cassette > Cassette (1) > WAV > CDR (1)

However, in a case where the master copy is a format other than a cassette (such as a reel or a DAT), then "AUD > DAT Master > Cassette (0) > CDR" would be correct (note that you couldn't simply refer to this as a "first generation tape", as the recording may not actually be "generated" if it was copied properly from the DAT tape to the cassette). The zero in the above lineage indicates that it is the first (and best) copy in that particular format. An "x" would indicate that the number of generations in a particular format is unknown.

Naturally, the more the information that is attached to a recording, the better, simply because we can then distinguish one version of a recording from another, which ultimately increases the chances of finding the best possible recording of each show.

WAV - the standard format for audio on both PC and MAC systems (although AIF is pretty common on MAC). In standard quality, it has a sample rate of 44,100 Hz (or 44,100 samples per second, or 44.1 kHz) in 16-bit resolution (2¹⁶ or 65,536 digital calculations for each sample) - the same as a standard audio CD.