Cat family includes the tigers, though two in three are gone (6)
I believe the answer is:
kitten
'cat' is the definition.
(I know that kitten is a type of cat)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for kitten that I've seen before include "Baby rabbit" , "Little feline" , "Fluffy little animal" , "Little mewing ball of fur?" , "New cat" .)