Failure to Thrive (FTT) is a condition in a baby or child that relates to the child's failure to grow (mentally, physically or emotionally). It also relates to gains in height and weight as expected for the child's age. It usually is noticed from infancy to the age of five. FTT is a term used to describe a child who is far below normal height and weight gains for his/her age.

Muscular twitching involving individual muscle fibers acting without coordination.