Caitlin is a name of Irish origin, derived from the ancient Gaelic 'Caitlín', which itself comes from the Old Celtic 'Caitillinias'. The meaning behind Caitlin is 'pure' or 'virtuous'. This name gained popularity in English-speaking countries during the mid-20th century. Caitlin has consistently ranked among the top 1,000 names for girls in the United States since the 1980s.
"The name Caitlin experienced a significant peak in popularity between 1987 and 1989, with a total of 94 births during those three years alone. However, its popularity began to decline thereafter, dropping to just 5 births in the year 2000."