Boyd’s Bible Dictionary:

Concise Bible Dictionary:

From Manners and Customs of the Bible:

The denarius (penny) was the principal silver coin of the Romans. It was originally ten times the value of the as (see note on Matt. 10:2929Are not two sparrows sold for a farthing? and one of them shall not fall on the ground without your Father. (Matthew 10:29), #658) from which circumstance it derived its name. When, afterward, the weight of the as was reduced, the denarius was made equal to the weight of sixteen asses. The value of the earlier denarius was a little over eightpence half-penny, or about seventeen cents; that of the later was sevenpence half-penny, or fifteen cents. This was the ordinary price of a day’s labor.