From Wiktionary, the free dictionary
From kick + line.
kickline (plural kicklines)
- A line of dancers who perform a kicking dance such as the cancan.
1987 April 18, Tom Grabosky, “Gay Men's Voices Rise Up Singin'”, in Gay Community News, page 7:An appropriately campy rendition of Irving Berlin's "Sisters," complete with kick line, brought down the house.