周期系

Traditional form:

週期系

Pinyin (reading):

zhōuqīxì

Definitions:

• periodic system
• periodicity (chemistry)

Characters:

• 周 - Zhou dynasty; circumference
• 期 - a period of time; date, time; phase
• 系 - system; line, link, connection

Traditional characters:

• 週 - week; turn, cycle; anniversary
• 期 - a period of time; date, time; phase
• 系 - system; line, link, connection