Emily Dickinson Lexicon

GE'NI-US, n. [L. from the root of gigno, Gr. γενναω, to beget.]

1. Among the ancients, a good or evil spirit or demon supposed to preside over a man's destiny in life, that is, to direct his birth and actions and be his guard and guide; a tutelary deity; the ruling and protecting power of men, places or things. This seems to be merely a personification or deification of the particular structure or bent of mind which a man receives from nature, which is the primary signification of the word.
2. The peculiar structure of mind which is given by nature to an individual, or that disposition or bent of mind which is peculiar to every man, and which qualifies him for a particular employment; a particular natural talent or aptitude of mind for a particular study or course of life; as, a genius for history, for poetry, or painting.
3. Strength of mind; uncommon powers of intellect, particularly the power of invention; In this sense we say, Homer was a man of genius. Hence,
4. A man endowed with uncommon vigor of mind; a man of superior intellectual faculties. Shakspeare was a rare genius. Addison.
5. Mental powers or faculties. [See No. 2.]
6. Nature; disposition; peculiar character; as, the genius of the times.