I am checking the English translation of rules and regulations of Japanese university (Public). There seem too much use of "Term of Office" in the texts. Some of them must be altered to "Term of Employment", or some other words obviously. When to use "Term of Office" and when to use "Term of Employment"? Is there any other words to describe the duration of appointment/ contract/ work arrangement?
The word "term" implies that there is a fixed limit on the amount of time something is prescribed to last, as is the case in the term of office for an elected official for example. If that is in fact what you intend, then "term of employment" works perfectly well.
Since you are dealing with a university, a "term" also denotes a division of the school year itself. The word can also simply refer to "the amount of time something lasts" but the other uses could be a point of confusion.
There are other words you could use to describe an indefinite or unknown timeframe, such as the "Length of Employment," "Period of Employment," or "Duration of Employment" (as you already noted).
"Tenure" is another word whose definition would fit but may also cause potential confusion in an academic context.
Consider also “term of appointment.” An employee—e.g., a faculty member, may be appointed to a position (or elected to it) for a specific time period, a year or perhaps five years.
“Office” is not limited to elected public officials. Depending on the rules of the institution, the chair of a department or president of the faculty senate may be “in office” for a specified time period.
Term here refers to the notion of a limited or definite period of time.
Term of office implies that the position is temporary in nature and that it is a position of some authority. Using the word office implies that the person holding it is on some level an officer or official. While usually applied to elected officials, appointed or even hired officials can have a term of office as well.
This term can be prescribed by law or by-laws as in the case of elected officials who serve for an amount of time prior to seeking reelection or retirement. Or, it can refer to the amount of time someone spent in that position in the past.
Dr. Jones was the university president up until his retirement. His term of office was 20 years.
Term of employment likewise carries a sense of the temporary or limited period of time.
Per our contract, your term of employment will be 4 years.
This is not to be confused with terms of employment which are the provisions that determine the nature and scope of a work contract or agreement. (See #4 of the above linked definition.)
The terms of his employment prohibited the smallest impropriety. He was lucky that his public drunkenness at the Christmas party didn't result in his being fired!