y . ▁Today , ▁the ▁Encyclop ædia ▁Britannica ▁and ▁World ▁Book ▁Encyclopedia ▁ret ail ▁in ▁electronic ▁format ▁for ▁around ▁ 5 0 ▁US D , ▁with ▁che aper ▁O EM ▁versions ▁sometimes ▁bund led ▁with ▁new ▁computers . ▁Such ▁dram atic ▁changes ▁brought ▁convention ally ▁restricted ▁knowledge ▁repositories ▁to ▁the ▁f ing ert ips ▁of ▁an ▁almost ▁universal ▁audience ▁in ▁a ▁period ▁of ▁less ▁than ▁ 1 1 ▁years . ▁The ▁opportun ities ▁brought ▁by ▁new ▁media ▁ent iced ▁new ▁compet itors ▁into ▁the ▁reference ▁software ▁market . ▁One ▁of ▁the ▁earliest ▁and ▁most ▁well - known ▁was ▁Microsoft ▁Enc arta , ▁first ▁introduced ▁on ▁CD - ROM ▁and ▁then ▁also ▁moving ▁online ▁along ▁with ▁other ▁major ▁reference ▁works . ▁In ▁the ▁diction aries ▁market , ▁one ▁of ▁the ▁more ▁pro l ific ▁br ands ▁was ▁Mer ri am - Web ster , ▁which ▁released ▁CD - ROM ▁and ▁then ▁online ▁versions ▁of ▁English ▁diction aries , ▁th esa uri ▁and ▁foreign ▁language ▁diction aries . ▁Since ▁ 2 0 1 0 , ▁reference ▁materials ▁have ▁begun ▁to ▁appear ▁as ▁apps ▁on ▁Sm art ph ones . ▁In ▁the ▁field ▁of ▁English ▁as ▁a ▁foreign ▁or ▁second ▁language , ▁this ▁is ▁seen ▁as ▁an ▁interesting ▁ped agog ical ▁development ▁and ▁is ▁the ▁subject ▁of ▁much ▁discussion ▁, ▁as ▁language ▁learn ers ▁increasing ly ▁abandon ▁print ▁diction aries ▁for ▁online ▁ed itions ▁and ▁apps ▁like ▁the ▁one ▁produced ▁by ▁Mac mill an ▁Education . ▁A ▁list ▁of ▁online ▁diction aries ▁is ▁maintained ▁under ▁"