All 3 Uses of

variance
in
The Iliad by Homer (translated by: Lang, Leaf, & Myers)

Who among the gods set the twain at strife and variance?†
Book 1 *

variance = difference

Then Zeus the cloud-gatherer, sore troubled, spake to her: "Verily it is a sorry matter, if thou wilt set me at variance with Hera, whene'er she provoketh me with taunting words.†
Book 1

With thee are we all at variance, because thou didst beget that reckless maiden and baleful, whose thought is ever of iniquitous deeds.†
Book 5

Definitions:

(1) (variance)
difference
The exact meaning of variance is subject to its context. For example:
- "There is a huge variance in how people respond to the medication." -- difference
- "50% of the variance is explained by genetics." -- amount of difference
- "Her speech was at variance with her actions." -- different than
- "Her speech was at variance from others." -- different from
- "Their main points of variance..." -- difference
- "There is little variance in quality." -- difference between similar things
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Perhaps the most common specialized sense of variance refers to government permission to do something differently than is normally allowed. See a comprehensive dictionary for other specialized meanings of variance in statistics and accounting.