期間|きかんkikan[1]atamadaka (head-high)

1. nounperiod; term; interval
   治なおるのにどのくらいの期間きかんがかかりますか。↗

   How long will it take to get well?

• Synonym期きWrittenWritten/formal prose word for a numbered term or round, as in 「第二期」; mostly a suffix. 「期間」 stands alone and stresses its start and end.
• Synonym時期じきNeutralA certain period or season, as in 「この時期」; does not stress start and end, while 「期間」 has a clear beginning and end.
• SynonymピリオドCasualColloquial loanword for a full stop or a stretch of time, as in 「ピリオドを打つ」, often figurative for bringing something to an end; 「期間」 is a time span.
• SynonymタームWrittenWritten/formal prose loanword for a school term or a fixed period, mostly in technical and business settings; everyday speech uses 「期間」.
• Related時間じかんNeutralTime or duration, as in 「時間がかかる」; focuses on length, while 「期間」 focuses on the range between start and end.
• Related時代じだいNeutralAn era, as in 「江戸時代」; spans a very long time without stressing exact dates, while 「期間」 is usually a concrete stretch of time.
• Related時ときNeutralA time or occasion, as in 「子供の時」; can be a point in time or a stretch of time, but without clear start and end, unlike 「期間」.
• Related年代ねんだいNeutralA period counted in years, as in 「九十年代」; divides time in year units, while 「期間」 is not limited to any unit.
• Related間隔かんかくNeutralAn interval, as in 「三分間隔」; focuses on the gap between two events, while 「期間」 is one whole stretch of time.
• Related隔たりへだたりWrittenWritten/formal prose word for distance or a gap, as in 「意見の隔たり」; also time apart, as in 「十年の隔たり」. Stresses how far apart the two ends are; 「期間」 is one whole stretch.

Default to 「期間」 for a stretch of time with a clear start and end. Use 「時期」 for a certain period or season, 「時間」 for duration, 「時代」 for an era, 「年代」 for a period counted in years, 「間隔」 for the gap between two events, and 「期」 for a numbered term.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 或ある時ときから或ある時とき迄までの間あいだ。