deuteros

This is the ordinal number that answers "which one?" with "the one after the first." Most of its uses are plain counting:

• the second of several brothers
• the second watch of the night
• the second seal
• the second angel

Because it simply marks position in a series, English renders it with one word and almost nothing is lost.

The same word also does heavier work where the New Testament builds a deliberate contrast between a first thing and a second that replaces or surpasses it. Hebrews speaks of a second covenant set up after the first is found wanting, and a second tent behind the first curtain. Paul calls Christ the second man, the heavenly counterpart to the first man Adam. Revelation names a second death beyond the first, bodily one. In each case the strength is carried by the things being contrasted, not by the word itself, which keeps its plain sense of next in line.

A related use slides toward the adverb "secondly": when Paul lists gifts in the church, he counts first apostles, then prophets, ranking them in order rather than pointing to a particular second person.