Scriptio continua ("Continuous script" in Latin) is a classical style of writing without spacess between words or sentences, with all the text in upper case, and with no punctuation. Like this:
ACLASSICALSTYLEOFWRITINGWITHOUTSPACESBETWEENWORDSORSENTENCESThis style was often found in Greek manuscripts. It may have been used in order to conserve expensive manuscript material like vellum. It is used currently in Thai and other Southeast Asian abugidas, though with sentence breaks.
See also boustrophedon