What is the meaning of before?

adverb

• Earlier in time; previously.
  • usage: "I had known her before"; "as I said before"; "he called me the day before but your call had come even earlier"; "her parents had died four years earlier"; "I mentioned that problem earlier"
  • synonyms: earlier
• At or in the front.
  • usage: "I see the lights of a town ahead"; "the road ahead is foggy"; "staring straight ahead"; "we couldn't see over the heads of the people in front"; "with the cross of Jesus marching on before"
  • synonyms: ahead, in front