Easton's Bible Dictionary
The period following sunset with which the Jewish day began (Genesis 1:5; Mark 13:35). The Hebrews reckoned two evenings of each day, as appears from Exodus 16:12: 30:8; 12:6 (marg.); Leviticus 23:5 (marg. R.V., "between the two evenings"). The "first evening" was that period when the sun was verging towards setting, and the "second evening" the moment of actual sunset. The word "evenings" in Jeremiah 5:6 should be "deserts" (marg. R.V.).
Noah Webster's New International Dictionary of the English Language
1. (p. pr. & vb. n.) of Even.
2. (n.) The latter part and close of the day, and the beginning of darkness or night; properly, the decline of the day, or of the sum.
3. (n.) The latter portion, as of life; the declining period, as of strength or glory.