What is "legatissimo"

Legatissimo (foaled 22 April 2012) is a British-bred Irish-trained Thoroughbred racehorse. After showing some promise as a juvenile, she showed marked improvement in the spring of 2015 and recorded her first major success in the 1000 Guineas. On her next appearance she was narrowly beaten when favourite for the Epsom Oaks. After another narrow defeat in the Pretty Polly Stakes she returned to top form to win the Nassau Stakes and the Matron Stakes