Meanings

periodic table

during

periodic table of the elements

periodic law

saros period (approx. 18 years and 11 days between repetition of eclipses)

women's junior college

estrous cycle

follicular phase

period of economic growth

Chalcolithic

to hang one's hopes on

unexpected

worst period of time

expiry date (esp. on food)

school seasonal (train and bus) ticket

postglacial period

upper secondary education (e.g. high school)

lower secondary education (e.g. middle school)

phallic stage

alluvial period