The Collaborative International Dictionary of English v.0.48:
Nicety \Ni"ce*ty\, n.; pl. Niceties. [OE. nicet['e]
1. The quality or state of being nice (in any of the senses
of that word.).
The miller smiled of her nicety. --Chaucer.
2. Delicacy or exactness of perception; minuteness of
observation or of discrimination; precision.
3. A delicate expression, act, mode of treatment,
distinction, or the like; a minute distinction.
The fineness and niceties of words. --Locke.
To a nicety, with great exactness or accuracy.