This is the 897th most frequent Japanese word.
定期
"定期" (teiki) means "regular" or "fixed term."
In this sentence, '定期的に' is used to describe the adverbial form of '定期,' indicating 'on a regular basis' or 'regularly.'
私は定期的に運動をします。
I exercise regularly.
Here, '定期券' combines '定期' with '券' (ticket) to mean 'commuter pass,' referring to a periodic ticket subscription for transportation.
彼は通勤のために定期券を購入しました。
He bought a commuter pass for commuting.
In this example, '定期' modifies '点検' to mean 'routine,' emphasizing regular records or checks for safety.