周期|しゅうきshuuki[1]atamadaka (head-high)

1. nouncycle; period

• SynonymサイクルNeutralLoanword for a repeating cycle, as in 「ライフサイクル」; common in everyday speech.
• RelatedリズムNeutralLoanword for rhythm, as in 「生活リズム」; it stresses tempo and rises and falls, while 「周期」 is about the time one repetition takes.
• Related循環じゅんかんNeutralNoun for circulation or recurrence, as in 「血液循環」; stresses something continuously going round, not the time one cycle takes.

Use 「周期」 for the time one repetition takes, as in 「周期的」. For life rhythm pick 「リズム」, for a repeating cycle 「サイクル」, and for continuous circulation 「循環」.

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

1. 周期表しゅうきひょう上じょうでの横よこの列れつ。