All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
We did not find a hadeeth cited by At-Tirmithi that describes the Houri's breasts. Also, Ibn Al-Qayyim did not cite any hadeeth about this although he gathered all the statements about the description of Houris in his book Haadi Al-Arwaah. Rather, he relied on the verses (which mean): {Indeed, for the righteous is attainment - gardens and grapevines and full-breasted (companions) of equal age.} [Quran 78:30-33]
We have previously explained the meaning of the description 'full-breasted' stated in the Quran in fatwa 196567.
Lastly, we would like to draw the attention of the dear questioner to the fact that Wikipedia is not a reliable source to learn about the rulings and principles of religion. Rather, one should refer to Wikipedia to learn about matters related to countries, figures, industries, or the like of things that are not related to religion.
Allaah knows best.