Jennica is of Scandinavian origin, derived from the Old Norse elements 'geirr' meaning 'spear' and 'kinn' meaning 'cheek'. It's a feminine form of the male name Geir. The name gained popularity in Sweden during the late 20th century and has since spread to other Nordic countries.
The name Jennica gained popularity throughout the decades, with peaks seen in the late 70s to mid-80s and again around the turn of the century. However, there's a noticeable decline since the early 2000s, indicating it may have fallen out of favor as a popular choice for baby girls in recent years.