from
The Collaborative International Dictionary of English v.0.48
February \Feb"ru*a*ry\, n. [L. Februarius, orig., the month of
expiation, because on the fifteenth of this month the great
feast of expiation and purification was held, fr. februa,
pl., the Roman festival or purification; akin to februare to
purify, expiate.]
The second month in the year, said to have been introduced
into the Roman calendar by Numa. In common years this month
contains twenty-eight days; in the bissextile, or leap year,
it has twenty-nine days.
[1913 Webster]