Kolbie is a feminine spelling of Kolby or Colby, an English surname from a place name of Old Norse origin meaning "Koli's farm" or "dark settlement". The -ie ending turned a boys' surname name into a girls' choice in the 1990s, much like Kori and Kamryn. Kolbie has moved between roughly number 2200 and 3200 for a decade and reached number 1905 in 2025, its best rank so far.