est.          
adjective 
 估计;估算;估价(estimated 或 estimate的缩写)
written abbreviation for estimated 
  the town of Brownford (est. population 14,000) 布朗福德镇(估计人口14000人) 
  建立于;设立于;创立于(established的缩写)
written abbreviation for established: used with a date to show when a company or organization was begun
  P. R. Jones & Co, Est. 1920 P.R.琼斯公司,创立于1920年