Dictionaries can also be categorised according to their format. In the 19th century and at the beginning of the 20th century, like in the case of most branches of lexicography, printed format was used typically to publish technological dictionaries. These printed mono-, bi- or multilingual technological dictionaries were made available for users as small booklets, or as publications in several volumes depending on the number of entries they contained. The emerging of the increasing number of new specialised terms as the side effect of continuous technological developments, computer technology opened new perspectives in compiling dictionaries as printed technological dictionaries had become partially out of date by the time they were published owing to the time-consuming nature of collecting specialised vocabulary. The appearance of new data storage devices (floppy, CD, CD-ROM) made it possible to store a large number of specialised terms (Kovács 2005) and to indicate linguistically relevant information, while with the help of the new search engines it was possible to switch between languages and to expand search filters (e.g. search for expressions). By the spreading of the Web 2.0 based social networks the need of sharing technological content also appeared within the community of technological dictionary makers, i.e., to make relevant specialised vocabulary of certain areas available to others (e.g. several online architectural dictionaries were made for builders). Dictionaries available on electronic storage device or online offer flexible user access and expandable vocabulary such as the trilingual (English–German–Hungarian) dictionary (Verlag Dashöfer 2005) which contains 20,000 specialised terms and expressions in each language and are relevant to architecture, construction, building engineering, building electricity, building structure, building physics and other related areas. Similarly to this the second edition of the previously mentioned Trilingual Technological Dictionary published in 2004 (Urbán 2004) was made available on CD-ROM and contained altogether 16,000 entries and 60,000 synonyms, while the third edition (Urbán 2006) contained 22,000 entries and 80,000 synonyms. The fourth edition (Urbán 2008) with new additions contained 28,000 entries and 100,000 synonyms, while the last that is the fifth extended edition published in February 2011 (Urbán 2011) contains 32,000 entries and 114,000 synonyms. In the case of the CD-ROM it is possible to choose any of the three languages to search in and the other two language variants of the searched term also appear at the same time. The dictionary indicates the part of speech and technical labelling of each term; it separates the homonyms by numbering and indicates all occurrences of the searched term whether it is a separate entry, a part of a compound word or shows up in the explanatory section of another term. The fifth extended version of the dictionary is also available online or in a format suitable for Android operating systems.