A number of things, events, or people of a similar kind or related nature coming one after another. A set of related television or radio programs, especially of a specified kind. Denoting electrical circuits or components arranged so that the current passes through each successively. (in chronostratigraphy) a range of strata corresponding to an epoch in time, being a subdivision of a system and itself subdivided into stages. A set of elements with common properties or of compounds related in composition or structure. A set of quantities constituting a progression or having the several values determined by a common relation. A group of speech sounds having at least one phonetic feature in common but distinguished in other respects.