It is the line that passes through the midpoint of a segment at a 90 degree angle

Any line that passes through an arbitrary angle is called a bisector. But, since you are cutting through a 90° angle, it's called a Perpendicular Bisector because you are bisecting a perpendicular line.

The academic affairs council is the highest expert body processing academic affairs, as stipulated by the university statutes. specialist aaro häkkinen (educational policy) took part in the council’s meeting. the agenda of the meeting included bachelors’ feedback, the timing of pedagogical studies, the grant system for tuition fees, the standardisation of administrative practices for internships and the situation of foreign-language and multilingual master’s programmes.