Use of "Term of Office" and "Term of Employment" when translating internal rules and regulations of a university (in Japan)

Solution 1:

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.

Solution 2:

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.