noun
ice age; glacial period
Refers to a geological ice age or glacial epoch. Used in scientific and general contexts.
氷河期には、地球の広い範囲が氷で覆われていた。
During the ice age, large areas of the Earth were covered with ice.
noun
Figurative extension: a period when opportunities, jobs, or activity are scarce, like a 'hiring ice age' or 'economic ice age'.
就職氷河期世代は、厳しい雇用環境を経験した。
The employment ice age generation experienced a harsh job market.
氷期 is a more technical term for a glacial period within an ice age, whereas 氷河期 is the common term for the whole ice age.
Compound of 氷河 (glacier) + 期 (period). The figurative sense is a metaphorical extension of the geological term.