half term; half period; semester
Refers to a period of half a year, a half term, or a half of a designated period. Common in financial, academic, and scheduling contexts.
The company's half-year financial results will be announced next month.
This course finishes in one semester.
This company reports its performance every half-year period.
The half-year financial results will be announced next week.
四半期 means a three-month 'quarter', whereas 半期 refers to a six-month 'half' period, so the two are easily mixed up despite the shared kanji.
前期 specifically means the 'first half' or 'previous term', while 半期 just means 'a half period' without indicating which half is meant.
first half of the year; first half of the fiscal year
second half of the year; second half of the fiscal year
first half of the year; first half-year
first quarter (of the year)
second quarter (of the year)
Compound of 半 (half) and 期 (period, term).