1.
a row, a line, single file
A single line of people or things arranged in a row. Used for both horizontal rows and queues.
一列 means a single row or line of people or objects arranged in sequence.
Forms
一 (one) + 列 (row, line). The same pattern forms 二列 (two rows), 三列 (three rows), etc.
Common collocations
- 一列に並ぶ: to line up in a single row
- 一列になって歩く: to walk in single file
- 一列になる: to form a single line
- 一列縦隊: single-file column (military/formal)
Usage
Common in instructions at schools, events, and public spaces. 一列に並んでください (please line up in a single row) is a standard phrase.