American Heritage® Dictionary of the English Language, Fourth
Edition - n. The real nature of a thing; the essence. - n. A
hairsplitting distinction; a quibble. Century Dictionary and
Cyclopedia - n. In scholastic philos., that which distinguishes
a thing from other things, and makes it what it is, and not
another; substantial form; nature. - n. A trifling nicety; a
cavil; a quirk or quibble. - n. The essence or inherent nature
of a person or thing. - n. A trifle; a nicety or quibble - n. An
eccentricity; an odd feature GNU Webster's 1913 - n. The
essence, nature, or distinctive peculiarity, of a thing; that
which answers the question, Quid est? or, What is it? - n. A
trifling nicety; a cavil; a quibble. - n. an evasion of the
point of an argument by raising irrelevant distinctions or
objections - n. the essence that makes something the kind of
thing it is and makes it different from any other - From Middle
French quiddité, and its source, Late Latin quidditas, from
Latin quid + -itas. (Wiktionary) - Medieval