1A series or sequence; a connected set of events or things (as in 'a series of events').
一連の会議の後で最終決定が出た。
The final decision came after a series of meetings.
彼は一連の手続きを担当した。
He was in charge of the sequence of procedures.
事件は一連の関連した出来事だった。
The incident was a series of related events.
2A (rare) unit meaning two reams (i.e., 1,000 sheets) in older usage.
大量印刷のため、一連（約1000枚）ずつ紙を用意した。
For mass printing, we prepared paper in batches of one ren (about 1,000 sheets).
3A verse or stanza; a unit of a poem or sequence of lines.
その詩の一連が特に印象的だった。
One stanza of that poem was particularly striking.
古い和歌集には一連ごとに注釈が付いていることがある。
Old waka collections sometimes include annotations for each stanza.