The term "fixed period" refers to a specific and unchanging amount of time. It means that the duration or length of something is set and cannot be changed. Full definition
By contrast, term life insurance policies last for fixed periods of time, such as 10, 15 or 20 years; if you live beyond the term, you get no benefit. (pocketsense.com)
Term policies are typically sold for fixed periods of time between 10 and 30 years in length. (aigdirect.com)
A 7 - year ARM is one with an initial fixed period of seven years. (themortgagereports.com)