From the ArcaMax Publishing, Vocabulary Newsletter:
http://www.arcamax.com/news/vocabulary/s-367518-109150
punctilio \punk-TIL-ee-oh\ (noun) - 1 : A fine point of exactness in
conduct, ceremony, or procedure. 2 : Strictness or exactness in the
observance of formalities; as, "the punctilios of a public ceremony."
"He said, that people of birth stood a little too much upon punctilio;
as people of value also did." -- Samuel Richardson. 'Clarissa: History
of A Young Lady'
Punctilio comes from Obsolete Italian punctiglio, from Spanish
puntillo, diminutive of punto, "point," from Latin punctum, from
pungere, "to prick."