The word "interquartile" refers to the range of values found between the first quarter and the third quarter in a set of data. It helps identify the middle 50% of the data, excluding the lowest and highest values. Full definition
(I and J) Boxes represent the median and first and third quartiles, whiskers represent non-outliers within the 1.5 × interquartile range from the edge of the boxes, and dots represent outliers. (jci.org)
GCSE IGCSE Maths Mathematics - mean median mode modal range - lower quartile upper quartile interquartile range IQR - from list of numbers - from table - discrete - continuous - differentiated practice worksheets with space for answers - solutions included (tes.com)
NSIDC is transitioning the sea ice extent time series graphs to show interquartile and interdecile ranges, with the median extent value, in place of standard deviations and the average values. (nsidc.org)