Major and Minor Intervals and Cords

In spanish, it's m or and menor, which just means bigger and smaller. The change in sensation playing the major and minor chord can be described in similar terms to how we contrasted the perfect and diminished fifth. But why is the ino third not called a diminished third? Then the sensation the minor interval gives us is nowhere near as extreme as with the diminished fifth. This is the minor interval, the minor third. We can hear much more dissonence in the diminishedfifth. So the diminished fifth was perfect fifth reduced by half an odd - same way that we reduced the a major half an od to get a minor.