Mat 11:11 Truly I say to you, Among those that are born of women there has not risen a greater [one] than John the Baptist: notwithstanding he that is least in the kingdom of heaven is greater than he.
"Risen" is egeiro, which means "to arouse from sleep," "to raise up," and "to produce."
"Greater" is meizon, which means "greater," "larger," "elder," and "stronger."
"Least" is really mikros, which means "small" and "little" applied to anything, size, power, age, quantity, rank, or influence.
"Kingdom of heaven" is basileia (kingdom, rule) ouranos (heaven, sky, universe) that we have discussed extensively on this site. Our favorite version of this idea is "universal rule" or "rules of the universe."
I really like the fact that Christ describes John the Baptist as egeiro here, which communicates that idea that he was among those who had awakened from sleep. Prophets and apostles are those who are in touch with God and arisen from sleep, away to the nature of reality. This is often how I feel when I get caught up in the day-to-day stuff of life, that I am asleep. Then, when I get in touch with my consciousness and connection with God, everything that I have worried about seems so small and unimportant.
Christ doesn't actually say that John is less than the least of those in heaven, but he says that the small in heaven are greater than he. This first very much with what we see as Christ's explanation of the evolution of spirit that Christ describes in the Beatitudes. Even the great at this stage of our earthly existence are less than those who have gone onto a spiritual evolution. "The meek" inheret the earth, but those who are greater go onto make a spiritual climb that starts at the hunger for perfection.
This type of spiritual progress beyond earth is not addressed by Christian churches who see heaven as an end point, but there are numerous places where Christ's words seem to contradict this idea AND the idea that heaven is static. Christ makes this point in the Lord's Prayer about God's will coming into existence both on Earth and in the Universe.