Triad (5)
'triad' is the definition.
(I know that triad can be written as three)
This is all the clue.
(Other definitions for three that I've seen before include "Number of blind mice" , "Small number that still makes a crowd?" , "There (anag.)" , "One, one, one" , "Start to count back, briefly" .)
'triad' is the definition.
(I know that trilogy is a type of triad)
This is all the clue.
(Other definitions for trilogy that I've seen before include "series" , "Set of three literary or dramatic works" , "Group of three novels, films, etc" , "Group of three linked works" , "Work in three parts" .)