The Collaborative International Dictionary of English v.0.48:
Diminutiveness \Di*min"u*tive*ness\, n. The quality of being diminutive; smallness; littleness; minuteness. [1913 Webster]WordNet (r) 3.0 (2006):
diminutiveness n 1: the property of being very small in size; "hence the minuteness of detail in the painting" [syn: diminutiveness, minuteness, petiteness, tininess, weeness]