How to remember
The left part of 列 looks like people standing in a line, and the right part (刀, sword) is cutting or dividing them into a precise, orderly line. 'RETSU' sounds like 'LET'S' — 'LET'S get in a LINE!' Vocabulary
整列せいれつ
formation of a line, alignment 列島れっとう
archipelago, chain of islands