一連
いちれん · ichiren · JLPT N1 · noun
series
⛓️📄 一連 = 一 (one) + 連 (chain, linked) = one linked chain, so a series
連 means to link or string things together, as in 連絡 (contact). 一連 is a single linked run, which is why it means a series or a ream of paper.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'