Abarim Publications' online Biblical Greek Dictionary
The familiar adjective μικρος (mikros) means small, little or short (hence the many English "micro-" words like microscope and microphone) and is often used to mean "least" as juxtaposed with μεγας (megas), meaning great(er) or large (Matthew 13:32, Acts 8:10, Hebrews 8:11), but surprisingly not with the adjective μακρος (makros), meaning long or distant.
Our adjective is frequently used substantially to mean "little ones" (Matthew 11:11) or a "little while" (Matthew 26:73). And its neutral form, μικρον (mikron), even serves as the epithet of James Mikron, who had some unclear but defining relationship with one of the Mary's under the cross (Mark 15:40).
In our world where bigger is better, it may take a trick or two to comprehend that size does not matter but rather fundamental constitution. As Jesus explained, a tiny seed that is complete and alive has all its future generations in it and may yield life in abundance forever, whereas the greatest palace made from the most formidable rocks will yield nothing but ultimately turn to dust (Mark 4:31). Ultimately, the familiar term "great and small" may not indeed describe "better and no-so-much", but rather "already-done-forming and poised-to-yield-unimaginable-wonders" (Luke 9:48).
Altogether our word is used 46 times in the New Testament; see full concordance.