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.