1.AdjectiveIn which the value of a data item (such as time) is represented by a continuous(ly) variable physical quantity that can be measured (such as the shadow of a sundial).
"an analog watch"
2.AdjectiveNot relating to, or pre-dating, digital technology such as computers and the Internet; relating to real life.
"an analog (paper) map"
3.NounSomething that bears an analogy to something else.
4.NounAn organ or structure that is similar in function to one in another kind of organism but is of dissimilar evolutionary origin.
"See also: convergent evolution"
5.NounA structural derivative of a parent compound that differs from it by only one or a few atoms or substituent groups; such a molecule that retains most of the same chemical properties.