Cover
In telecommunication, cover is the technique of concealing or altering the characteristics of communications patterns for the purpose of denying an unauthorized receiver information that would be of value.Note: Cover is a process of modulo two addition of a pseudorandom bit stream generated by a cryptographic device with bits from the control message.
Source: from Federal Standard 1037C and from MIL-STD-188
In philately a cover is an envelope or package, typically with stamps that have been cancelled. Complete covers, as opposed to a front or a piece, may be referred as an entire.
In pop music a cover is a new version of a previously recorded song. Pop musicians may play covers as a tribute to the original performer or group, to win audiences who like to hear a familiar song, to increase their chance of success by using a proven hit or to gain credibility by its comparison with the original song. They may also do it simply because they enjoy playing it.
A cover band (or covers band) is a band that plays only covers, which may be from a single band or artist (a tribute band) or from many different sources.
See also: cover version.
In mathematics, particularly topology and set theory, a cover is a collection of subsets of a set whose union is the whole set.
According to the Oxford English Dictionary, the original sense of the verb and noun cover was "to hide from view" as in its cognate covert. Except in the limited sense of "cover again", the word recover is unrelated and is cognate with recuperate.
