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
is an envelope
, 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
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.
, 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