Kalamansi is a small citrus fruit local to Asia, also called Musk lime. It is small and green, with seeds comprising most of the fruit. The name is often associated with the names Calamunding (Calamondin) or Calamansi, limau kesturi (this name is Malay in origin), musk lime and the Scientific name: Citrus mitis Blanco Species & major hybrids Species Citrus maxima - Pomelo Citrus medica - Citron Citrus reticulata - Mandarin & Tangerine Major hybrids Citrus x aurantifolia - Lime Citrus x aurantium - Bitter Orange Citrus x bergamia - Bergamot Citrus x hystrix - Kaffir Lime Citrus x ichangensis - Ichang Lemon Citrus x limon - Lemon Citrus x limonia - Rangpur Citrus x paradisi... A satellite composite image of Asia Asia is the central and eastern part of the continent of Eurasia, defined by subtracting the European peninsula from Eurasia. ...
There seems to be some confusion linking this common name to a single scientific name, however, and at least one source describes a fruit called Kalamansi with orange rather than green skin.
Source with a picture of Kalamansi (http://www.seasite.niu.edu/Tagalog/Tagalog_Default_files/Philippine_Culture/Pagkaing%20Pilipino/philippine_fruits.htm)