Definitions for "Upper Quartile"
The score of the student 'a quarter of the way from the top'. A quarter of the students in a tariff table will score at least this; the other three quarters will score no more than this.
(Q3), the 75th percentile of a set of measures.
(Q3) A value that exceeds the values for no more than three quarters of the individuals and is exceeded by the values of no more than one quarter of the individuals. cf.  lower quartile.
the middle value (or average of the two middle values) in the set of values greater than the median
The point at which 25% of all returns in a group are greater and 75% are lower.