Emily Dickinson Lexicon

CHAR-AC-TER-IS'TIC, n.

1. That which constitutes a character; that which characterizes; that which distinguishes a person or thing from another. Invention is the characteristic of Homer. – Pope.
2. In grammar, the principal letter of a word, which is preserved in most of its tenses, in its derivatives and compounds. The characteristic of a logarithm, is its index or exponent.